Fix Pointing Device code (#1934)

* Fix pointer device options

when the feature was added, the appropriate option definition wasn't created.  This needs to be added to function properly.

* Update common_features.mk

* missing underscore in init function declaration

common_features.mk

@@ -70,6 +70,7 @@ ifeq ($(strip $(FAUXCLICKY_ENABLE)), yes)
 endif
 
 ifeq ($(strip $(POINTING_DEVICE_ENABLE)), yes)
+    OPT_DEFS += -DPOINTING_DEVICE_ENABLE
     SRC += $(QUANTUM_DIR)/pointing_device.c
 endif
 

quantum/pointing_device.h

@@ -22,7 +22,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "host.h"
 #include "report.h"
 
-void pointingdevice_init(void);
+void pointing_device_init(void);
 void pointing_device_task(void);
 void pointing_device_send(void);
 report_mouse_t pointing_device_get_report(void);