bcm27xx: add support for RPI A, A+, 3A+, Zero2 and Zero2W

bcm27xx: add support for RPI A, A+, 3A+, Zero2 and Zero2W

These devices were already supported. I merely added missing entries to:
1. make them easier to locate in firmware selector
2. allow firmware upgrades to proceed without dire warnings

Sample dire warning contains:
    upgrade: Device raspberrypi,model-zero-2-w not supported by this image
    upgrade: Supported devices: rpi-3-b rpi-3-b-plus rpi-zero-2 \
      raspberrypi,2-model-b-rev2 raspberrypi,3-model-b \
      raspberrypi,3-model-b-plus raspberrypi,3-compute-module \
      raspberrypi,compute-module-3 raspberrypi,model-zero-2

With this patch, the firmware upgrade proceeds normally.

Signed-off-by: Dave Brand <dbrand666@users.noreply.github.com>