broadcom_sta: 6.30.223.248 -> 6.30.223.271

The patch for kernel version 3.18 is already applied upstream, so we
don't need it any longer.

Without i686-build-failure.patch, the build for i686-linux fails because
it references rdtscl(), which is no longer available in Linux 4.3.0.

Patch for missing rdtscl() is from Arch Linux:

https://aur.archlinux.org/cgit/aur.git/tree/002-rdtscl.patch?h=broadcom-wl-ck

I've tested building against 32 and 64 bit Linux versions 3.18.36,
4.4.16 and 4.7.0.

The hashes were verified using the ones from the AUR (using the 16 bit
hashes of course):

$ nix-hash --type sha256 --to-base16 1kaqa2dw3nb8k23ffvx46g8jj3wdhz8xa6jp1v3wb35cjfr712sg
4f8b70b293ac8cc5c70e571ad5d1878d0f29d133a46fe7869868d9c19b5058cd
$ nix-hash --type sha256 --to-base16 1gj485qqr190idilacpxwgqyw21il03zph2rddizgj7fbd6pfyaz
5f79774d5beec8f7636b59c0fb07a03108eef1e3fd3245638b20858c714144be

AUR hashes can be found at:

https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=broadcom-wl&id=9d6f10b1b7745fbf5d140ac749e2253caf70daa8#n26



Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @phreedom, @vcunat