regulator: lp8788-ldo: make array en_mask static const, makes object smaller

regulator: lp8788-ldo: make array en_mask static const, makes object smaller

Don't populate the array en_mask on the stack but instead make it
static const. Makes the object code smaller by 87 bytes.

Before:
   text	   data	    bss	    dec	    hex	filename
  12967	   3408	      0	  16375	   3ff7	drivers/regulator/lp8788-ldo.o

After:
   text	   data	    bss	    dec	    hex	filename
  12816	   3472	      0	  16288	   3fa0	drivers/regulator/lp8788-ldo.o

(gcc version 9.2.1, amd64)

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20190906130632.6709-1-colin.king@canonical.com
Signed-off-by: Mark Brown <broonie@kernel.org>