ARM: dts: qcom: Introduce dtsi for LTE-capable MSM8926

MSM8926, while being 'just' an LTE-capable variant of MSM8226, the dts
needs to slightly change since the modem doesn't use the ext-bhs-reg and
needs mss-supply, therefore it gets a new compatible.

Since we already have two -common.dtsi files which are used on both
APQ8026/MSM8226 and MSM8926 devices, change the setup a bit by removing
the SoC include from those and requiring the device dts to pick the
correct one.

Reviewed-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
Link: https://lore.kernel.org/r/20250217-msm8226-modem-v5-11-2bc74b80e0ae@lucaweiss.eu


Signed-off-by: Bjorn Andersson <andersson@kernel.org>