powerpc/85xx: Fix pixis_reset altbank mask on MPC8536DS

Currently, pixis_reset altbank does not work properly. This patch
uses the correct mask to boot into the alternate bank.

Signed-off-by: Matthew McClintock <msm@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

include/configs/MPC8536DS.h

@@ -311,7 +311,7 @@
 /* old pixis referenced names */
 #define PIXIS_VCLKH		0x19	/* VELA VCLKH register */
 #define PIXIS_VCLKL		0x1A	/* VELA VCLKL register */
-#define CONFIG_SYS_PIXIS_VBOOT_MASK	0xc0
+#define CONFIG_SYS_PIXIS_VBOOT_MASK	0x4e
 
 #define CONFIG_SYS_INIT_RAM_LOCK	1
 #define CONFIG_SYS_INIT_RAM_ADDR	0xffd00000	/* Initial L1 address */