media: venus: Limit HFI sessions to the maximum supported

[ Upstream commit 20891170 ]

Currently we rely on firmware to return error when we reach the maximum
supported number of sessions. But this errors are happened at reqbuf
time which is a bit later. The more reasonable way looks like is to
return the error on driver open.

To achieve that modify hfi_session_create to return error when we reach
maximum count of sessions and thus refuse open.

Tested-by: Fritz Koenig <frkoenig@chromium.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Stable-dep-of: 9edaaa8e ("media: venus: hfi_parser: refactor hfi packet parsing logic")
Signed-off-by: Sasha Levin <sashal@kernel.org>