package/linux-firmware: add rpi settings files

package/linux-firmware: add rpi settings files

The brcmfmac drivers now load settings files for BCM434xx devices and
fail if they're missing on the Raspberry Pi:

brcmfmac mmc1:0001:1: Direct firmware load for brcm/brcmfmac43455-sdio.raspberrypi,3-model-b-plus.txt failed with error -2

This commit copies the missing settings files over to the firmware
directory with the other files.

Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>