libbsd: fix libpath to not use host path
libpath.so uses host path in ld script causing other packages fail to
cross compile, e.g. perl:
"ld: cannot find /usr/lib/libbsd.so.0.11.6: No such file or directory"
Fixes: openwrt/packages#19390
Signed-off-by: Xuefer H <[email protected]>