Move setexpr to Kconfig

Another shell scripting command that has not been moved.

Moved using tools/moveconfig.py using these settings:

CMD_SETEXPR bool n y

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/configs/P5020DS_defconfig b/configs/P5020DS_defconfig
index d1c5c72..0ea13fb 100644
--- a/configs/P5020DS_defconfig
+++ b/configs/P5020DS_defconfig
@@ -1,3 +1,4 @@
 CONFIG_PPC=y
 CONFIG_MPC85xx=y
 CONFIG_TARGET_P5020DS=y
+CONFIG_CMD_SETEXPR=y