libcamera: move PACKAGECONFIG def to meta-oe

Move the raspberrypi PACKAGECONFIG to meta-oe (at least partially),
as the libcamera recipe needs to know when is it built for an rpi due
to a new build dependency. Also, make the PACKAGECONFIG append device
specific. Otherwise the behavior of the bbappend should not change
by this patch.

Signed-off-by: Gyorgy Sarvari <skandigraun@gmail.com>

dynamic-layers/multimedia-layer/recipes-multimedia/libcamera/libcamera_%.bbappend

@@ -1,3 +1,3 @@
-PACKAGECONFIG[raspberrypi] = "-Dpipelines=rpi/vc4 -Dipas=rpi/vc4"
+EXTRA_OEMESON:append:rpi = " -Dipas=rpi/vc4,rpi/pisp"
 PACKAGECONFIG:append:rpi = " raspberrypi"
 CXXFLAGS:append:rpi = " -Wno-unaligned-access "