treewide: remove PKG_INSTALL from CMake packages

It's already default with cmake.mk

Found with:

git grep PKG_INSTALL\: | cut -d ':' -f 1 | sort -u > ins
git grep cmake.mk | cut -d ':' -f 1 > cmake
comm -1 -2 ins cmake

Signed-off-by: Rosen Penev <rosenp@gmail.com>

package/system/opkg/Makefile

@@ -26,8 +26,6 @@ PKG_CONFIG_DEPENDS += \
 	CONFIG_SIGNATURE_CHECK \
 	CONFIG_TARGET_INIT_PATH
 
-PKG_INSTALL:=1
-
 HOST_BUILD_DEPENDS:=libubox/host
 
 include $(INCLUDE_DIR)/package.mk