Enable RTC on the CM4 I/O board

Include the kernel modules in the initramfs to set the clock as early as
possible.

config.txt

@@ -55,3 +55,6 @@ upstream_kernel=1
 # https://fedoraproject.org/w/index.php?title=Architectures/ARM/Raspberry_Pi/HATs
 
 dtoverlay=disable-bt
+
+# Enable the i2c RTC on the CM4 I/O board
+dtoverlay=i2c-rtc,pcf85063a,i2c_csi_dsi

mkinitramfs.sh

@@ -24,7 +24,7 @@ chroot "${destdir}" dracut \
     --no-hostonly \
     --modules 'nbd udev-rules dracut-systemd shutdown' \
     --drivers 'genet nbd squashfs' \
-    --force-drivers 'bcm2835_wdt' \
+    --force-drivers 'bcm2835_wdt i2c_bcm2835 i2c_mux_pinctrl rtc_pcf85063' \
     --force \
     /boot/initramfs.img \
     "${kver}"