dtoverlays: Update CSI overlays to use i2c_csi_dsi

Update all overlays that were using i2c_vc for talking to CSI
source devices to use the new i2c_csi_dsi node via i2c_mux_pinctrl.
Remove the pins overrides as well.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>