firmware: qcom_scm: Convert all symbols to EXPORT_SYMBOL_GPL

The `qcom_scm` module is GPL v2-licenced and so there is no reason why
the APIs it exports should not be, too.

Signed-off-by: Guru Das Srinagesh <quic_gurus@quicinc.com>
Reviewed-by: Trilok Soni <quic_tsoni@quicinc.com>
Link: https://lore.kernel.org/r/19d9ac0bf79f957574ef9b3b73246ea0113cc0fd.1690503893.git.quic_gurus@quicinc.com


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