package/runc: drop <pkg>_WORKSPACE variable

With the go.mod integration, the <pkg>_WORKSPACE variable has become
useless, so drop it.

Signed-off-by: Christian Stewart <christian@paral.in>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/runc/runc.mk

@@ -9,10 +9,7 @@ RUNC_SITE = $(call github,opencontainers,runc,v$(RUNC_VERSION))
 RUNC_LICENSE = Apache-2.0
 RUNC_LICENSE_FILES = LICENSE
 
-RUNC_WORKSPACE = Godeps/_workspace
-
 RUNC_LDFLAGS = -X main.gitCommit=$(RUNC_VERSION)
-
 RUNC_TAGS = cgo static_build
 
 ifeq ($(BR2_PACKAGE_LIBSECCOMP),y)