media: venus: core,pm: fix potential infinite loop

The for-loop iterates with a u8 loop counter i and compares this
with the loop upper limit of res->resets_num which is an unsigned
int type.  There is a potential infinite loop if res->resets_num
is larger than the u8 loop counter i. Fix this by making the loop
counter the same type as res->resets_num.

Addresses-Coverity: ("Infinite loop")

Fixes: 3bca4358 ("media: venus: core,pm: Add handling for resets")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>