media: venus: core: Hook to V6 base registers when appropriate

This commit points the IO base registers 6xx offsets when probing for 6xx
hardware.

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>