regulator: max77650: Fix include files

This is a platform driver, no need to include linux/i2c.h.
Include linux/of.h for of_match_ptr.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>