firmware: qcom_scm: Move qcom_scm.h to include/linux/firmware/qcom/

Move include/linux/qcom_scm.h to include/linux/firmware/qcom/qcom_scm.h.
This removes 1 of a few remaining Qualcomm-specific headers into a more
approciate subdirectory under include/.

Suggested-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Guru Das Srinagesh <quic_gurus@quicinc.com>
Acked-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230203210956.3580811-1-quic_eberman@quicinc.com