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