Kconfigs: Correct default of "0" on hex type entries

It is not a parse error to have a default value of "0" for a "hex" type
entry, instead of "0x0".  However, "0" and "0x0" are not treated the
same even by the tools themselves. Correct this by changing the default
value from "0" to "0x0" for all hex type questions that had the
incorrect default. Fix one instance (in two configs) of a default of "0"
being used on a hex question to be "0x0". Remove the cases where a
defconfig had set a value of "0x0" to be used as the default had been
"0".

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index d94b582..2136ab7 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -181,7 +181,7 @@
 config SPL_IMX_ROMAPI_LOADADDR
 	hex "Default load address to load image through ROM API"
 	depends on IMX8_ROMAPI || SPL_BOOTROM_SUPPORT
-	default 0
+	default 0x0
 
 config IMX_DCD_ADDR
 	hex "DCD Blocks location on the image"
diff --git a/arch/arm/mach-imx/imx8/Kconfig b/arch/arm/mach-imx/imx8/Kconfig
index 15f844f..59d11b3 100644
--- a/arch/arm/mach-imx/imx8/Kconfig
+++ b/arch/arm/mach-imx/imx8/Kconfig
@@ -34,11 +34,11 @@
 
 config BOOTAUX_RESERVED_MEM_BASE
 	hex "i.MX auxiliary core dram memory base"
-	default 0
+	default 0x0
 
 config BOOTAUX_RESERVED_MEM_SIZE
 	hex "i.MX auxiliary core dram memory size"
-	default 0
+	default 0x0
 
 choice
 	prompt "i.MX8 board select"