added rpi4 device

devices/rpi4

+## Maintained by Strit ##
+
+# Kernel and Bootloader stuff
+linux-aarch64
+uboot-raspberrypi
+raspberrypi-bootloader
+
+# Other device specific packages
+firmware-raspberrypi
+pi-bluetooth
+wpa_supplicant
+
+# Video driver
+xf86-video-fbturbo-git