common, kconfig: Fix defaut value of BOOTSTAGE_STASH_SIZE

The default value of BOOTSTAGE_STASH_SIZE should be set to hexadecimal,
but an integer value is set. This fixes the BOOTSTAGE_STASH_SIZE number
from hexadecimal to integer.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/common/Kconfig b/common/Kconfig
index 1e0c627..ec519d0 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -90,7 +90,7 @@
 
 config BOOTSTAGE_STASH_SIZE
 	hex "Size of boot timing stash region"
-	default 4096
+	default 0x1000
 	help
 	  This should be large enough to hold the bootstage stash. A value of
 	  4096 (4KiB) is normally plenty.