net: qrtr: fix build problems

Having multiple loadable modules with the same name cannot work
with modprobe, and having both net/qrtr/smd.ko and drivers/soc/qcom/smd.ko
results in a (somewhat cryptic) build error:

ERROR: "qcom_smd_driver_unregister" [net/qrtr/smd.ko] undefined!
ERROR: "qcom_smd_driver_register" [net/qrtr/smd.ko] undefined!
ERROR: "qcom_smd_set_drvdata" [net/qrtr/smd.ko] undefined!
ERROR: "qcom_smd_send" [net/qrtr/smd.ko] undefined!
ERROR: "qcom_smd_get_drvdata" [net/qrtr/smd.ko] undefined!
ERROR: "qcom_smd_driver_unregister" [drivers/soc/qcom/wcnss_ctrl.ko] undefined!
ERROR: "qcom_smd_driver_register" [drivers/soc/qcom/wcnss_ctrl.ko] undefined!
ERROR: "qcom_smd_set_drvdata" [drivers/soc/qcom/wcnss_ctrl.ko] undefined!
ERROR: "qcom_smd_send" [drivers/soc/qcom/wcnss_ctrl.ko] undefined!
ERROR: "qcom_smd_get_drvdata" [drivers/soc/qcom/wcnss_ctrl.ko] undefined!

Also, the qrtr driver uses the SMD interface and has a Kconfig dependency,
but also allows for compile-testing when SMD is disabled. However, if
with QCOM_SMD=m and COMPILE_TEST=y we can end up with QRTR_SMD=y and
that fails with a related link error.

The changes the dependency so we can still compile-test the driver but
not have it built-in if SMD is a module, to avoid running in the broken
configuration, and changes the Makefile to provide the driver under
a different module name.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: bdabad3 ("net: Add Qualcomm IPC router")
Signed-off-by: David S. Miller <davem@davemloft.net>

net/qrtr/Kconfig

@@ -16,7 +16,7 @@ if QRTR
 
 config QRTR_SMD
 	tristate "SMD IPC Router channels"
-	depends on QCOM_SMD || COMPILE_TEST
+	depends on QCOM_SMD || (COMPILE_TEST && QCOM_SMD=n)
 	---help---
 	  Say Y here to support SMD based ipcrouter channels.  SMD is the
 	  most common transport for IPC Router.

net/qrtr/Makefile

@@ -1,2 +1,4 @@
 obj-$(CONFIG_QRTR) := qrtr.o
-obj-$(CONFIG_QRTR_SMD) += smd.o
+
+obj-$(CONFIG_QRTR_SMD) += qrtr-smd.o
+qrtr-smd-y	:= smd.o