media: ti-vpe: cal: move code to separate functions

To make csi2_wait_for_phy() more readable, move code to separate
functions.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil-cisco@xs4all.nl: delete empty line before } ]
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>