brcmfmac: fix BRCMF_FW_NVRAM_DEF macro for older gcc compilers

With gcc < 4.3 __UNIQUE_ID does not create unique ids with the macro
BRCMF_FW_NVRAM_DEF. Fix this by removing the MODULE_FIRMWARE instance
for the nvram file. This file is not in linux-firmware repo so it may
not be needed anyway. Otherwise consider this as a temporary fix.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arend van Spriel <aspriel@gmail.com>
Acked-by: Kalle Valo <kvalo@codeaurora.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>