mvebu: add kmod-i2c-mux-pca954x for Turris Omnia

The driver is for the I2C mux.
Schematic available at https://doc.turris.cz/doc/_media/rtrom01-schema.pdf

Signed-off-by: Josef Schlehofer <josef.schlehofer@nic.cz>
Tested-by: Rosen Penev <rosenp@gmail.com>

target/linux/mvebu/image/cortex-a9.mk

@@ -173,7 +173,7 @@ define Device/cznic_turris-omnia
   DEVICE_PACKAGES :=  \
     mkf2fs e2fsprogs kmod-fs-vfat kmod-nls-cp437 kmod-nls-iso8859-1 \
     wpad-basic kmod-ath9k kmod-ath10k-ct ath10k-firmware-qca988x-ct \
-    partx-utils
+    partx-utils kmod-i2c-core kmod-i2c-mux kmod-i2c-mux-pca954x
   IMAGES := $$(IMAGE_PREFIX)-sysupgrade.img.gz omnia-medkit-$$(IMAGE_PREFIX)-initramfs.tar.gz
   IMAGE/$$(IMAGE_PREFIX)-sysupgrade.img.gz := boot-img | sdcard-img | gzip | append-metadata
   IMAGE/omnia-medkit-$$(IMAGE_PREFIX)-initramfs.tar.gz := omnia-medkit-initramfs | gzip