ram: rockchip: rename sdram.h to sdram_rk3288.h

The header file sdram.h is used for rk3288 and similar SoCs, rename it
to make it more understandable.

Signed-off-by: YouMin Chen <cym@rock-chips.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/ram/rockchip/sdram_rk3288.c b/drivers/ram/rockchip/sdram_rk3288.c
index 5775254..3b6c4a0 100644
--- a/drivers/ram/rockchip/sdram_rk3288.c
+++ b/drivers/ram/rockchip/sdram_rk3288.c
@@ -20,7 +20,7 @@
 #include <asm/arch-rockchip/ddr_rk3288.h>
 #include <asm/arch-rockchip/grf_rk3288.h>
 #include <asm/arch-rockchip/pmu_rk3288.h>
-#include <asm/arch-rockchip/sdram.h>
+#include <asm/arch-rockchip/sdram_rk3288.h>
 #include <asm/arch-rockchip/sdram_common.h>
 #include <linux/err.h>
 #include <power/regulator.h>