Convert CONFIG_SPL_NAND_SUPPORT to Kconfig

Move this option to Kconfig and tidy up existing uses.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/cpu/armv7/omap3/Kconfig b/arch/arm/cpu/armv7/omap3/Kconfig
index 48b596a..98056b1 100644
--- a/arch/arm/cpu/armv7/omap3/Kconfig
+++ b/arch/arm/cpu/armv7/omap3/Kconfig
@@ -24,6 +24,9 @@
 config SPL_MMC_SUPPORT
 	default y
 
+config SPL_NAND_SUPPORT
+	default y
+
 choice
 	prompt "OMAP3 board select"
 	optional
diff --git a/arch/arm/cpu/armv7/omap4/Kconfig b/arch/arm/cpu/armv7/omap4/Kconfig
index b92220a..15287af 100644
--- a/arch/arm/cpu/armv7/omap4/Kconfig
+++ b/arch/arm/cpu/armv7/omap4/Kconfig
@@ -24,6 +24,9 @@
 config SPL_MMC_SUPPORT
 	default y
 
+config SPL_NAND_SUPPORT
+	default y
+
 choice
 	prompt "OMAP4 board select"
 	optional
diff --git a/arch/arm/cpu/armv7/omap5/Kconfig b/arch/arm/cpu/armv7/omap5/Kconfig
index e74a867..3186202 100644
--- a/arch/arm/cpu/armv7/omap5/Kconfig
+++ b/arch/arm/cpu/armv7/omap5/Kconfig
@@ -24,6 +24,9 @@
 config SPL_MMC_SUPPORT
 	default y
 
+config SPL_NAND_SUPPORT
+	default y
+
 choice
 	prompt "OMAP5 board select"
 	optional
diff --git a/arch/arm/mach-socfpga/Kconfig b/arch/arm/mach-socfpga/Kconfig
index 6aeabdb..87402e1 100644
--- a/arch/arm/mach-socfpga/Kconfig
+++ b/arch/arm/mach-socfpga/Kconfig
@@ -12,6 +12,9 @@
 config SPL_MMC_SUPPORT
 	default y if DM_MMC
 
+config SPL_NAND_SUPPORT
+	default y if SPL_NAND_DENALI
+
 config TARGET_SOCFPGA_ARRIA5
 	bool
 	select TARGET_SOCFPGA_GEN5
diff --git a/arch/arm/mach-uniphier/Kconfig b/arch/arm/mach-uniphier/Kconfig
index 4c7300c..7c75348 100644
--- a/arch/arm/mach-uniphier/Kconfig
+++ b/arch/arm/mach-uniphier/Kconfig
@@ -9,6 +9,9 @@
 config SPL_MMC_SUPPORT
 	default y if !ARCH_UNIPHIER_64BIT
 
+config SPL_NAND_SUPPORT
+	default y if !ARM64
+
 config SYS_CONFIG_NAME
 	default "uniphier"