package/janus-gateway: enable parallel build

Parallel build is fixed since version 0.4.4 and
https://github.com/meetecho/janus-gateway/commit/1685a78e2cd7642f6246466c2e0d4e670fe6360b

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/janus-gateway/janus-gateway.mk

@@ -117,7 +117,4 @@ else
 JANUS_GATEWAY_CONF_OPTS += --disable-websockets
 endif
 
-# Parallel build broken
-JANUS_GATEWAY_MAKE = $(MAKE1)
-
 $(eval $(autotools-package))