musl: Update to latest

musl: Update to latest

Brings following bug fixes

* 79bdacff glob: fix wrong return code when aborting before any matches
* 7291c6c6 statvfs: allocate spare for f_type
* 39e43f08 math: fix ld80 powl(x,huge) and powl(LDBL_MAX,small)
* 6d101027 math: fix ld80 acoshl(x) for x < 0

Drop MIRRORS and switch to etalabs.net for git fetch URI
original repo is not working correcting with git Fetcher

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>