Add SRAM binding documentation.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NTomasz Figa <t.figa@samsung.com>
[kgene.kim@samsung.com: changed name SRAM to SYSRAM]
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>