brcm: Add brcmfmac43455-sdio.raspberrypi,3-model-a-plus.txt symlink

The Raspberry Pi 3A+ uses the same WiFi module and NVRAM as the 3B+ and
Raspbian uses the same file for both models so we can symlink the 3A+ to
the 3B+ to have WiFi work on those devices too.
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Cc: Matthias Brugger <mbrugger@suse.com>
Reviewed-by: Matthias Brugger <mbrugger@suse.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -2624,6 +2624,7 @@ File: "brcm/brcmfmac43430-sdio.Hampoo-D2D3_Vi8A1.txt"
 File: "brcm/brcmfmac43430-sdio.MUR1DX.txt"
 File: "brcm/brcmfmac43430-sdio.raspberrypi,3-model-b.txt"
 File: "brcm/brcmfmac43455-sdio.raspberrypi,3-model-b-plus.txt"
+Link: brcm/brcmfmac43455-sdio.raspberrypi,3-model-a-plus.txt -> brcm/brcmfmac43455-sdio.raspberrypi,3-model-b-plus.txt
 File: "brcm/brcmfmac43455-sdio.raspberrypi,4-model-b.txt"
 File: "brcm/brcmfmac43455-sdio.MINIX-NEO Z83-4.txt"
 File: "brcm/brcmfmac4356-pcie.gpd-win-pocket.txt"