staging/mt29f_spinand: coding style fixes

This patch fixes the coding style error :
"WARNING: else is not generally useful after a break or return"
reported by checkpatch.pl

Signed-off-by: Vibi Sreenivasan <vibisreenivasan@linuxmail.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>