package/erofs-utils: fix build with gcc 4.8

Add upstream patch to disable -Werror and fix the following build
failure with gcc 4.8 raised since bump to version 1.4 in commit
c2e32e65 and
https://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git/commit/?id=cf8be8a4352a5df3b3acf545af289cb47faa6de0:

In file included from /home/buildroot/autobuild/instance-0/output-1/host/arm-buildroot-linux-gnueabi/sysroot/usr/include/string.h:636:0,
                 from ../include/erofs/internal.h:242,
                 from ../include/erofs/inode.h:11,
                 from main.c:12:
In function 'memset',
    inlined from 'erofsdump_filetype_distribution.constprop.2' at main.c:583:9:
/home/buildroot/autobuild/instance-0/output-1/host/arm-buildroot-linux-gnueabi/sysroot/usr/include/bits/string3.h:81:30: error: call to '__warn_memset_zero_len' declared with attribute warning: memset used with constant zero length parameter; this could be due to transposed parameters [-Werror]
       __warn_memset_zero_len ();
                              ^

Fixes:
 - http://autobuild.buildroot.org/results/4c776ec935bbb016231b6701471887a7c9ea79e9



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>