ARM: OMAP: sram: fix OMAP4 errata handling

OMAP4-specific code should be executed only if we are running on
OMAP4. Otherwise it may break multi-OMAP kernels. Found by reading
the code.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/sram.c

@@ -175,8 +175,10 @@ static void __init omap_map_sram(void)
 		return;
 
 #ifdef CONFIG_OMAP4_ERRATA_I688
+	if (cpu_is_omap44xx()) {
 		omap_sram_start += PAGE_SIZE;
 		omap_sram_size -= SZ_16K;
+	}
 #endif
 	if (cpu_is_omap34xx()) {
 		/*