remoteproc: qcom_q6v5_mss: Add modem support on MSM8926

remoteproc: qcom_q6v5_mss: Add modem support on MSM8926

While MSM8926 being 'just' an LTE-capable variant of MSM8226 it appears
the modem setup has changed significantly, by requiring mss-supply and
not using the ext-bhs-reg.

Add a new compatible and new struct to support that.

Reviewed-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
Link: https://lore.kernel.org/r/20250217-msm8226-modem-v5-6-2bc74b80e0ae@lucaweiss.eu
Signed-off-by: Bjorn Andersson <andersson@kernel.org>