imgtec/pistachio: memlayout: update GRAM size

GRAM is 421056 bytes. The end of the SRAM region (GRAM plays the role
of SRAM) was placed at a 4K aligned address, resulting in a size of
408KB.

Change-Id: I9fa32ab818d600e7447bcac895e4b8c438f2f99d
Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com>
Reviewed-on: https://review.coreboot.org/12772
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/soc/imgtec/pistachio/include/soc/memlayout.ld

@@ -39,7 +39,7 @@ SECTIONS
 	ROMSTAGE(0x1a005000, 40K)
 	VBOOT2_WORK(0x1a00f000, 12K)
 	PRERAM_CBFS_CACHE(0x1a012000, 56K)
-	SRAM_END(0x1a020000)
+	SRAM_END(0x1a066000)
 
 	/* Bootblock executes out of KSEG0 and sets up the identity mapping.
 	 * This is identical to SRAM above, and thus also limited 64K and