regulator: mp5416: remove kernel.h include

Driver does not seem to utilize anything from the kernel.h, compiles
and works fine for me without it.

So remove kernel.h include as it pulls in a lot of unused stuff.
Signed-off-by: Robert Marko <robimarko@gmail.com>
Cc: christophe.jaillet@wanadoo.fr
Link: https://lore.kernel.org/r/20220607124759.775133-1-robimarko@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/mp5416.c

@@ -9,7 +9,6 @@
 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
-#include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>