mtd: sst25l: fix section markings

mtd: sst25l: fix section markings

The previous section mismatch fix for this driver wasn't entirely correct.
The sst25l_flash_info array is now used in the devinit probe func, but is
marked as initdata, so building results in the warning:

WARNING: drivers/mtd/devices/sst25l.o(.devinit.text): Section mismatch
	in reference from the function sst25l_probe()
	to the variable .init.data:sst25l_flash_info

Further, the remove func should be devexit rather than exit to match the
probe func.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>