WHENCE: add missing symlink for BananaPi M3

Fixes (Debian bug #982579):
> [   11.957171] brcmfmac mmc2:0001:1: firmware: failed to load
brcm/brcmfmac43430-sdio.sinovoip,bpi-m3.txt (-2)
> [   11.967106] firmware_class: See https://wiki.debian.org/Firmware

 for
information about missing firmware
> [   11.977035] brcmfmac mmc2:0001:1: firmware: failed to load
brcm/brcmfmac43430-sdio.txt (-2)
> [   12.994756] brcmfmac: brcmf_sdio_htclk: HT Avail timeout (1000000): clkctl
0x50

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