Remove volatile qualifier in get_ram_size() calls

Checkpatch.pl complains about the volatile qualifier in calls to
get_ram_size(). Remove this qualifier in the prototype and in the
calls where it is useless, and leave it only in the function body
where it is needed.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
diff --git a/board/freescale/mx31pdk/mx31pdk.c b/board/freescale/mx31pdk/mx31pdk.c
index 08addd2..f6e190a 100644
--- a/board/freescale/mx31pdk/mx31pdk.c
+++ b/board/freescale/mx31pdk/mx31pdk.c
@@ -42,7 +42,7 @@
 int dram_init(void)
 {
 	/* dram_init must store complete ramsize in gd->ram_size */
-	gd->ram_size = get_ram_size((volatile void *)CONFIG_SYS_SDRAM_BASE,
+	gd->ram_size = get_ram_size((void *)CONFIG_SYS_SDRAM_BASE,
 				PHYS_SDRAM_1_SIZE);
 	return 0;
 }