gdb: unbreak host-gdb with python support if python3 is enabled

Fixes http://autobuild.buildroot.net/results/ef4/ef487b495e57f098af0fe9508d430b56b0750339/

Explicitly pass the path to host-python to ensure it gets used.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gdb/gdb.mk

@@ -146,7 +146,7 @@ else
 endif
 
 ifeq ($(BR2_PACKAGE_HOST_GDB_PYTHON),y)
-	HOST_GDB_CONF_OPTS += --with-python
+	HOST_GDB_CONF_OPTS += --with-python=$(HOST_DIR)/usr/bin/python2
 	HOST_GDB_DEPENDENCIES += host-python
 else
 	HOST_GDB_CONF_OPTS += --without-python