mtd: lpc32xx_slc: Make wp gpio optional

This patch supports missing wp gpio.

Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>
Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
1 file changed