powerpc/85xx: Bump up the CONFIG_SYS_BOOTM_LEN to 64M on FSL 85xx boards

CONFIG_SYS_BOOTMAPSZ has been 64M on these boards for some time so we
should also allow the kernel image to be up to 64M decompressed.  This
also matches what we pass to the OS based on the ePAPR specification.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/include/configs/P2020DS.h b/include/configs/P2020DS.h
index cee9fd4..b5db0b3 100644
--- a/include/configs/P2020DS.h
+++ b/include/configs/P2020DS.h
@@ -709,11 +709,11 @@
 
 /*
  * For booting Linux, the board info and command line data
- * have to be in the first 16 MB of memory, since this is
+ * have to be in the first 64 MB of memory, since this is
  * the maximum mapped by the Linux kernel during initialization.
  */
-#define CONFIG_SYS_BOOTMAPSZ	(16 << 20)	/* Initial Memory map for Linux*/
-#define CONFIG_SYS_BOOTM_LEN	(16 << 20)	/* Increase max gunzip size */
+#define CONFIG_SYS_BOOTMAPSZ	(64 << 20)	/* Initial Memory map for Linux*/
+#define CONFIG_SYS_BOOTM_LEN	(64 << 20)	/* Increase max gunzip size */
 
 #if defined(CONFIG_CMD_KGDB)
 #define CONFIG_KGDB_BAUDRATE	230400	/* speed to run kgdb serial port */