media: venus: Add support for SSR trigger using fault injection

Here we introduce a new fault injection for SSR trigger.

To trigger the SSR:
echo 100 > /sys/kernel/debug/venus/fail_ssr/probability
echo 1 > /sys/kernel/debug/venus/fail_ssr/times

Co-developed-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: venus: place extern venus_fw_debug on a header file

Sparse warns about this symbol:

drivers/media/platform/qcom/venus/hfi_venus.c:133:5: warning: symbol 'venus_fw_debug' was not declared. Should it be static?

Because hfi_venus.c doesn't include a header file with the
extern. So, move it to core.h, with is included by both
hfi_venus.c and dbgfs.c.

This way, if something changes with it, warnings or errors
will be produced.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: venus: Add debugfs interface to set firmware log level

This will be useful when debugging specific issues related to
firmware HFI interface.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>