hostapd: fix musl issues

hostapd: fix musl issues

Add two patches to fix build issues with the musl libc.

The first patch "0003-vlan-fix-musl-build-error" fixes the undefined __caddr_t
build error. __caddr_t is a legacy BSD type and should be avoided in modern
implementations.

The second patch "0004-vlan-fix-musl-libc-conflict-with-Linux-kernel-header"
fixes a typical musl libc header conflict with the Linux kernel header. We avoid
including the conflicting Linux header file by defining the needed macros
directly in the needing hostapd source file.

Fixes:
http://autobuild.buildroot.net/results/c26/c265cfada20621a631e9d118b9633df80b0e4864/
http://autobuild.buildroot.net/results/658/658c5e2fe6e3a4ad74ca47c926426e95eac0b9ec/
http://autobuild.buildroot.net/results/578/5787805b3e1487c4f85c3a367ed88e8730078b8e/
http://autobuild.buildroot.net/results/42d/42d8be008dcb07e9ec26ce10c797deb43ed86568/

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>