bridge-utils: fix build with musl

Apply a patch that removes direct include of kernel headers to avoid conflict
of definitions.

Fixes:
http://autobuild.buildroot.net/results/4aa/4aaeca4f1fca1794b039d7255a1828ff724f2234/
http://autobuild.buildroot.net/results/b48/b48a70137a4a568b31337f899fd21d05552db5e2/
http://autobuild.buildroot.net/results/bff/bff5767fc7e821a7674ee022111db84e4a9449d0/



Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>