regulator: lp872x: fix a build waring and coding styles

Fix a warning below.

  drivers/regulator/lp872x.c:910:33: warning: cast from pointer to integer of
                                     different size [-Wpointer-to-int-cast]

And checkpatch warnings are fixed.

  WARNING: space prohibited before semicolon

Signed-off-by: Milo Kim <milo.kim@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>