misc: sram: enable clock before registering regions

Make sure to enable the clock before registering regions and exporting
partitions to user space at which point we must be prepared for I/O.

Fixes: ee895ccd ("misc: sram: fix enabled clock leak on error path")
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>