firmware: qcom_scm: QCOM_SCM should depend on ARCH_QCOM

The Qualcomm Secure Channel Manager (SCM) is only present on Qualcomm
SoCs.  All drivers using it select QCOM_SCM, and depend on ARCH_QCOM.
Until recently, QCOM_SCM was an invisible symbol, but this was changed
by adding loadable module support, exposing it to all ARM and ARM64
users.  Hence add a dependency on ARCH_QCOM, to prevent asking the user
about this driver when configuring a kernel without Qualcomm SoC
support.

While at it, drop the dependency on ARM || ARM64, as that is implied by
HAVE_ARM_SMCCC.

Fixes: b42000e4 ("firmware: qcom_scm: Allow qcom_scm driver to be loadable as a permenent module")
Fixes: 2954a6f1 ("firmware: qcom-scm: Fix QCOM_SCM configuration")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/5cda77085c07dc2e8d2195507b287457cb2f09e9.1629807831.git.geert+renesas@glider.be