pixbufcache.bbclass: remove a dependency loop introduced by enabling gtk+3-native

(From OE-Core rev: f99921554fddef82eb80568125aa646a27859a4b)

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/pixbufcache.bbclass

@@ -3,7 +3,7 @@
 # packages.
 #
 
-DEPENDS += "qemu-native"
+DEPENDS_append_class-target = " qemu-native"
 inherit qemu
 
 PIXBUF_PACKAGES ??= "${PN}"