media: venus: hfi, vdec: v6 Add IS_V6() to existing IS_V4() if locations

In various places in the venus codebase we have if (IS_V4()) which takes
the code down paths for 4xx silicon. This logic is broadly applicable to
6xx silicon also. In this patch we add IS_V6() to various IS_V4() decision
locations.

Co-developed-by: Dikshita Agarwal <dikshita@qti.qualcomm.com>
Signed-off-by: Dikshita Agarwal <dikshita@qti.qualcomm.com>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>