net: ethernet: ti: build cpsw-common for switchdev

Without the common part of the driver, the new file fails to link:

drivers/net/ethernet/ti/cpsw_new.o: In function `cpsw_probe':
cpsw_new.c:(.text+0x312c): undefined reference to `ti_cm_get_macid'

Use the same Makefile hack as before, and build cpsw-common.o for
any driver that needs it.

Fixes: ed3525e ("net: ethernet: ti: introduce cpsw switchdev based driver part 1 - dual-emac")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

drivers/net/ethernet/ti/Makefile

@@ -5,6 +5,7 @@
 
 obj-$(CONFIG_TI_CPSW) += cpsw-common.o
 obj-$(CONFIG_TI_DAVINCI_EMAC) += cpsw-common.o
+obj-$(CONFIG_TI_CPSW_SWITCHDEV) += cpsw-common.o
 
 obj-$(CONFIG_TLAN) += tlan.o
 obj-$(CONFIG_CPMAC) += cpmac.o