[media] omap3isp: csiphy: Fix an uninitialized variable compiler warning

drivers/media/platform/omap3isp/ispcsiphy.c: In function
‘csiphy_routing_cfg’:
drivers/media/platform/omap3isp/ispcsiphy.c:71:57: warning: ‘shift’
may be used uninitialized in this function [-Wuninitialized]
drivers/media/platform/omap3isp/ispcsiphy.c:40:6: note: ‘shift’ was
declared here
The warning is a false positive but the compiler is right in
complaining. Fix it by using the correct enum data type for the iface
argument and adding a default case in the switch statement.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>