remoteproc: mss: q6v5-mss: Add modem support on SC7280

Add out of reset sequence support for modem sub-system on SC7280 SoCs.
It requires access to an additional set of qaccept registers, external
power/clk control registers and halt vq6 register to put the modem back
into reset.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1631886935-14691-6-git-send-email-sibis@codeaurora.org