Misc: sram: Remove unneeded check

Patch removes unneeded check for resource since
devm_ioremap_resource do all for us.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>