Convert ARCH_OMAP2PLUS boards' CONFIG_SYS_TEXT_BASE to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_TEXT_BASE

The includes, whitelist, etc. were left for now but I don't get any
build errors or warnings on the omap3_logic_defconfig or
am3517_evm_defconfig builds I tried.

Signed-off-by: Adam Ford <aford173@gmail.com>
diff --git a/Kconfig b/Kconfig
index c1451bc..286d1c7 100644
--- a/Kconfig
+++ b/Kconfig
@@ -335,12 +335,14 @@
 config SYS_TEXT_BASE
 	depends on ARC || X86 || ARCH_UNIPHIER || ARCH_ZYNQMP || \
 		(M68K && !TARGET_ASTRO_MCF5373L) || MICROBLAZE || MIPS || \
-		ARCH_ZYNQ || ARCH_KEYSTONE
+		ARCH_ZYNQ || ARCH_KEYSTONE || ARCH_OMAP2PLUS
 	depends on !EFI_APP
 	hex "Text Base"
 	help
 	  TODO: Move CONFIG_SYS_TEXT_BASE for all the architecture
 
+	default 0x80800000 if ARCH_OMAP2PLUS
+
 
 config SYS_CLK_FREQ
 	depends on ARC || ARCH_SUNXI