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/drivers/block/Kconfig b/drivers/block/Kconfig
index 6baaa6f..1abea3f 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -167,7 +167,7 @@
 
 config SYS_ATA_BASE_ADDR
 	hex "Base address of IDE controller"
-	default 0
+	default 0x0
 	help
 	  This is the address of the IDE controller, from which other addresses
 	  are calculated. Each bus is at a fixed offset from this address,