brcm: Fix a stale symlink for RPi3 model b+

The symlink for brcmfmac43455-sdio.raspberrypi,3-model-b-plus.txt
was wrongly listed with the same subdirectory brcm, and this resulted
in a stale symlink.  Fix it.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -2639,7 +2639,7 @@ 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
+Link: brcm/brcmfmac43455-sdio.raspberrypi,3-model-a-plus.txt -> 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"