remoteproc: qcom_adsp_pil: select qcom_scm

remoteproc: qcom_adsp_pil: select qcom_scm

The adsp-pil driver relies on SCM and causes a build error without it:

ERROR: "qcom_scm_pas_supported" [drivers/remoteproc/qcom_adsp_pil.ko] undefined!
ERROR: "qcom_scm_is_available" [drivers/remoteproc/qcom_adsp_pil.ko] undefined!
ERROR: "qcom_scm_pas_auth_and_reset" [drivers/remoteproc/qcom_adsp_pil.ko] undefined!
ERROR: "qcom_scm_pas_shutdown" [drivers/remoteproc/qcom_adsp_pil.ko] undefined!
ERROR: "qcom_scm_pas_mem_setup" [drivers/remoteproc/qcom_adsp_pil.ko] undefined!
ERROR: "qcom_scm_pas_init_image" [drivers/remoteproc/qcom_adsp_pil.ko] undefined!

This adds a 'select', as SCM is a silent Kconfig symbol that gets
enabled implicitly by all its users.

Fixes: b9e718e950c3 ("remoteproc: Introduce Qualcomm ADSP PIL")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>