media: vivid: fix potential integer overflow on left shift

There is a potential integer overflow when int 2 is left shifted
as this is evaluated using 32 bit arithmetic but is being used in
a context that expects an expression of type s64.  Fix this by
generating a mask using GENMASK to avoid a 32 bit overflow.

Addresses-Coverity: ("Unintentional integer overflow")

Fixes: 8a99e9fa ("media: vivid: add HDMI (dis)connect RX emulation")
Fixes: 79a792da ("media: vivid: add HDMI (dis)connect TX emulation")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>