media: gspca: cpia1: shift-out-of-bounds in set_flicker

Syzkaller reported the following issue:
UBSAN: shift-out-of-bounds in drivers/media/usb/gspca/cpia1.c:1031:27
shift exponent 245 is too large for 32-bit type 'int'

When the value of the variable "sd->params.exposure.gain" exceeds the
number of bits in an integer, a shift-out-of-bounds error is reported. It
is triggered because the variable "currentexp" cannot be left-shifted by
more than the number of bits in an integer. In order to avoid invalid
range during left-shift, the conditional expression is added.

Reported-by:  <syzbot+e27f3dbdab04e43b9f73@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/all/20230818164522.12806-1-coolrrsh@gmail.com
Link: https://syzkaller.appspot.com/bug?extid=e27f3dbdab04e43b9f73


Signed-off-by: Rajeshwar R Shinde <coolrrsh@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>