remoteproc: mss: q6v5-mss: Add modem support on SC7180

Add the out of reset sequence support for modem sub-system on SC7180
SoCs. It requires access to an additional halt nav register to put
the modem back into reset.
Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20191219054506.20565-3-sibis@codeaurora.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>