arch: Make board selection choices optional

By making the board selections optional, every defconfig will include
the board selection when running savedefconfig so if a new board is
added to the top of the list of choices the former top's defconfig will
still be correct.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Cc: Tom Rini <trini@konsulko.com>
diff --git a/arch/powerpc/cpu/mpc512x/Kconfig b/arch/powerpc/cpu/mpc512x/Kconfig
index a0f0ede..53450ae 100644
--- a/arch/powerpc/cpu/mpc512x/Kconfig
+++ b/arch/powerpc/cpu/mpc512x/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_PDM360NG
 	bool "Support pdm360ng"
diff --git a/arch/powerpc/cpu/mpc5xx/Kconfig b/arch/powerpc/cpu/mpc5xx/Kconfig
index aad4a7c..5275447 100644
--- a/arch/powerpc/cpu/mpc5xx/Kconfig
+++ b/arch/powerpc/cpu/mpc5xx/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_CMI_MPC5XX
 	bool "Support cmi_mpc5xx"
diff --git a/arch/powerpc/cpu/mpc5xxx/Kconfig b/arch/powerpc/cpu/mpc5xxx/Kconfig
index eec9d7d..5d49228 100644
--- a/arch/powerpc/cpu/mpc5xxx/Kconfig
+++ b/arch/powerpc/cpu/mpc5xxx/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_A3M071
 	bool "Support a3m071"
diff --git a/arch/powerpc/cpu/mpc8260/Kconfig b/arch/powerpc/cpu/mpc8260/Kconfig
index 55941c8..e93732d 100644
--- a/arch/powerpc/cpu/mpc8260/Kconfig
+++ b/arch/powerpc/cpu/mpc8260/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_KM82XX
 	bool "Support km82xx"
diff --git a/arch/powerpc/cpu/mpc83xx/Kconfig b/arch/powerpc/cpu/mpc83xx/Kconfig
index 88a3bd6..3fb901f 100644
--- a/arch/powerpc/cpu/mpc83xx/Kconfig
+++ b/arch/powerpc/cpu/mpc83xx/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_MPC8308_P1M
 	bool "Support mpc8308_p1m"
diff --git a/arch/powerpc/cpu/mpc85xx/Kconfig b/arch/powerpc/cpu/mpc85xx/Kconfig
index aff5fdb..3e8d0b1 100644
--- a/arch/powerpc/cpu/mpc85xx/Kconfig
+++ b/arch/powerpc/cpu/mpc85xx/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_SBC8548
 	bool "Support sbc8548"
diff --git a/arch/powerpc/cpu/mpc86xx/Kconfig b/arch/powerpc/cpu/mpc86xx/Kconfig
index 14e8b1a..fe1859d 100644
--- a/arch/powerpc/cpu/mpc86xx/Kconfig
+++ b/arch/powerpc/cpu/mpc86xx/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_SBC8641D
 	bool "Support sbc8641d"
diff --git a/arch/powerpc/cpu/mpc8xx/Kconfig b/arch/powerpc/cpu/mpc8xx/Kconfig
index e8bcbe9..79cee35 100644
--- a/arch/powerpc/cpu/mpc8xx/Kconfig
+++ b/arch/powerpc/cpu/mpc8xx/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_TQM823L
 	bool "Support TQM823L"
diff --git a/arch/powerpc/cpu/ppc4xx/Kconfig b/arch/powerpc/cpu/ppc4xx/Kconfig
index 4d5954a..10b86e0 100644
--- a/arch/powerpc/cpu/ppc4xx/Kconfig
+++ b/arch/powerpc/cpu/ppc4xx/Kconfig
@@ -6,6 +6,7 @@
 
 choice
 	prompt "Target select"
+	optional
 
 config TARGET_CSB272
 	bool "Support csb272"