file: Convert to BBCLASSEXTEND

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

meta/packages/file/file-native_4.18.bb

@@ -1,8 +0,0 @@
-require file_${PV}.bb
-inherit native
-
-# avoid dependency loop
-DEPENDS = ""
-PR = "r1"
-
-SRC_URI += "file://native-fix.diff;patch=1"

meta/packages/file/file_4.18.bb

@@ -15,3 +15,7 @@ do_configure_prepend() {
 	cp ${WORKDIR}/dump ${S}/magic/Magdir/
 	cp ${WORKDIR}/filesystems ${S}/magic/Magdir/
 }
+
+DEPENDS_virtclass-native = ""
+SRC_URI_append_virtclass-native = " file://native-fix.diff;patch=1"
+BBCLASSEXTEND = "native"