main/linux-grsec: only build -dev package for supported arch/flavor

this fixes build on armhf which previously built linux-virtgrsec-dev
package even if there are no linux-virtgrsec for armhf.

main/linux-grsec/APKBUILD

@@ -27,7 +27,7 @@ source="https://kernel.org/pub/linux/kernel/v4.x/linux-$_kernver.tar.xz
 	config-virtgrsec.x86
 	config-virtgrsec.x86_64
 	"
-subpackages="$pkgname-dev:_dev linux-virtgrsec-dev:_dev"
+subpackages="$pkgname-dev:_dev"
 _flavors=
 for _i in $source; do
 	case $_i in
@@ -36,7 +36,7 @@ for _i in $source; do
 		_f=${_f#config-}
 		_flavors="$_flavors ${_f}"
 		if [ "linux-$_f" != "$pkgname" ]; then
-			subpackages="$subpackages linux-${_f}"
+			subpackages="$subpackages linux-${_f} linux-${_f}-dev:_dev"
 		fi
 		;;
 	esac