kernel: iio: fix st-accel missing dependency

Fixes following build error on mpc85xx/p2020:

 Package kmod-iio-st_accel is missing dependencies for the following libraries:
  regmap-core.ko

Fixes: 2d8f4c4fbd46 ("kernel: iio: add st-accel driver modules")
Signed-off-by: Petr Štetiar <[email protected]>

package/kernel/linux/modules/iio.mk

@@ -281,7 +281,7 @@ $(eval $(call KernelPackage,iio-si7020))
 define KernelPackage/iio-st_accel
   SUBMENU:=$(IIO_MENU)
   TITLE:=STMicroelectronics accelerometer 3-Axis Driver
-  DEPENDS:=+kmod-iio-core
+  DEPENDS:=+kmod-iio-core +kmod-regmap-core
   KCONFIG:= \
 	CONFIG_IIO_ST_ACCEL_3AXIS \
 	CONFIG_IIO_ST_SENSORS_CORE