Add symlink for BananaPi M2 to brcmfmac43430-sdio config

Fixes ( Debian bug #982579 [1]):
 [   10.514530] brcmfmac mmc2:0001:1: firmware: direct-loading firmware brcm/brcmfmac43430-sdio.bin
 [   10.514732] brcmfmac mmc2:0001:1: firmware: failed to load brcm/brcmfmac43430-sdio.sinovoip,bpi-m2-ultra.txt ( -2)

Refs:
[1] https://bugs.debian.org/982579

Reported-by: Bernhard <bewoern1@gmail.com>
Signed-off-by: maximilian attems <maks@stro.at>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -2716,6 +2716,7 @@ File: "brcm/brcmfmac43430a0-sdio.ONDA-V80 PLUS.txt"
 File: "brcm/brcmfmac43430-sdio.AP6212.txt"
 Link: brcm/brcmfmac43430-sdio.sinovoip,bpi-m2-plus.txt -> brcmfmac43430-sdio.AP6212.txt
 Link: brcm/brcmfmac43430-sdio.sinovoip,bpi-m2-zero.txt -> brcmfmac43430-sdio.AP6212.txt
+Link: brcm/brcmfmac43430-sdio.sinovoip,bpi-m2-ultra.txt -> brcmfmac43430-sdio.AP6212.txt
 File: "brcm/brcmfmac43430-sdio.Hampoo-D2D3_Vi8A1.txt"
 File: "brcm/brcmfmac43430-sdio.MUR1DX.txt"
 File: "brcm/brcmfmac43430-sdio.raspberrypi,3-model-b.txt"