mfd: Constify struct mfd_cell where possible

As of commit 03e361b25ee8dfb1fd9b890072c23c4aae01c6c7 ("mfd: Stop setting
refcounting pointers in original mfd_cell arrays"), the "cell" parameter of
mfd_add_devices() is "const" again. Hence make all cell data passed to
mfd_add_devices() const where possible.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/lp8788.c b/drivers/mfd/lp8788.c
index 0f12219..a30bc15 100644
--- a/drivers/mfd/lp8788.c
+++ b/drivers/mfd/lp8788.c
@@ -71,7 +71,7 @@
 	},
 };
 
-static struct mfd_cell lp8788_devs[] = {
+static const struct mfd_cell lp8788_devs[] = {
 	/* 4 bucks */
 	MFD_DEV_WITH_ID(BUCK, 1),
 	MFD_DEV_WITH_ID(BUCK, 2),