firmware: bcm47xx_sprom: Fix -Wmissing-prototypes warnings

bcm47xx_sprom.h did not include a prototype for bcm47xx_fill_sprom()
therefore add one, and make sure we do include that header to fix
-Wmissing-prototypes warnings.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MIPS: BCM47xx: Move SPROM driver to drivers/firmware/

Broadcom ARM home routers store SPROM content in NVRAM just like MIPS
ones. To share SPROM code we need to move it out of arch/mips/ to some
common place. We already have bcm47xx_nvram in firmware path and SPROM
should fit there as well.
This driver is responsible for parsing SoC configuration data into a
struct shared between ssb and bcma buses.
This was tested with BCM4706 & BCM5357C0 (BCM47XX) and BCM4708A0
(ARCH_BCM_5301X).

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12210/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>