AM3517:EMIF4: fix SDRAM size to 256Mb

With addition of "dram_init_banksize()" function from Heiko,Schocher
(commit ID: 561142af20f1fd7b425d9425730014e656defb91), the DRAM size
is getting configured wrongly to 512Mb (CS0 & CS1).
So fix it to 256Mb.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>

arch/arm/cpu/armv7/omap3/emif4.c

@@ -48,10 +48,11 @@ u32 is_mem_sdr(void)
  */
 u32 get_sdr_cs_size(u32 cs)
 {
-	u32 size;
+	u32 size = 0;
 
 	/* TODO: Calculate the size based on EMIF4 configuration */
-	size = CONFIG_SYS_CS0_SIZE;
+	if (cs == CS0)
+		size = CONFIG_SYS_CS0_SIZE;
 
 	return size;
 }