remoteproc: qcom: fix QCOM_SMD dependencies

qcom_smd_register_edge() is provided by either QCOM_SMD or RPMSG_QCOM_SMD,
and if both of them are disabled, it does nothing.

The check for the PIL drivers however only checks for QCOM_SMD, so it breaks
with QCOM_SMD=n && RPMSG_QCOM_SMD=m:

drivers/remoteproc/built-in.o: In function `smd_subdev_remove':
qcom_wcnss_iris.c:(.text+0x231c): undefined reference to `qcom_smd_unregister_edge'
drivers/remoteproc/built-in.o: In function `smd_subdev_probe':
qcom_wcnss_iris.c:(.text+0x2344): undefined reference to `qcom_smd_register_edge'
drivers/remoteproc/built-in.o: In function `smd_subdev_probe':
qcom_q6v5_pil.c:(.text+0x3538): undefined reference to `qcom_smd_register_edge'
qcom_q6v5_pil.c:(.text+0x3538): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `qcom_smd_register_edge'

This clarifies the Kconfig dependency.

Fixes: 4b48921a ("remoteproc: qcom: Use common SMD edge handler")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>