ltp: Replace musl patches with do_patch[postfuncs]

MUSL related build fixes are not going to be upstreamed.  They just not
compile broken files, thus replace them with upstream solution for CI:
just deleting files for musl (easier to maintain).

Signed-off-by: Petr Vorel <petr.vorel@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>