ARM: add permission annotations to MT_MEMORY* mapping types

Document the permissions which the various MT_MEMORY* mapping types
will provide.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-omap2/omap4-common.c b/arch/arm/mach-omap2/omap4-common.c
index 5791143..08def56 100644
--- a/arch/arm/mach-omap2/omap4-common.c
+++ b/arch/arm/mach-omap2/omap4-common.c
@@ -88,7 +88,7 @@
 	dram_io_desc[0].virtual = OMAP4_DRAM_BARRIER_VA;
 	dram_io_desc[0].pfn = __phys_to_pfn(paddr);
 	dram_io_desc[0].length = size;
-	dram_io_desc[0].type = MT_MEMORY_SO;
+	dram_io_desc[0].type = MT_MEMORY_RW_SO;
 	iotable_init(dram_io_desc, ARRAY_SIZE(dram_io_desc));
 	dram_sync = (void __iomem *) dram_io_desc[0].virtual;
 	sram_sync = (void __iomem *) OMAP4_SRAM_VA;