northbridge/amd/amdfam10: Correct S3_DATA_POS type from int to hex

This resolves a Kconfig warning.

Change-Id: Ic77c8bf89613c116dfdc73572709aeb354e33b2a
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/12287
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
Tested-by: build bot (Jenkins)

src/northbridge/amd/amdfam10/Kconfig

@@ -95,8 +95,8 @@ config S3_DATA_SIZE
 	depends on (HAVE_ACPI_RESUME)
 
 config S3_DATA_POS
-	int
-	default 0
+	hex
+	default 0x0
 	depends on (HAVE_ACPI_RESUME)
 
 if DIMM_DDR2