ltp: Filter out -ffile-prefix-map

ffile-prefix-map is also needed for reproduble builds and when
introduced can be handled

(From OE-Core rev: 1f8132450b0192ad0c9f35f8b5dbac186c240e29)

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

meta/recipes-extended/ltp/ltp_20210121.bb

@@ -76,6 +76,7 @@ do_install(){
     find ${D}${prefix} -name Makefile | xargs -n 1 sed -i \
          -e 's@[^ ]*-fdebug-prefix-map=[^ "]*@@g' \
          -e 's@[^ ]*-fmacro-prefix-map=[^ "]*@@g' \
+         -e 's@[^ ]*-ffile-prefix-map=[^ "]*@@g' \
          -e 's@[^ ]*--sysroot=[^ "]*@@g'
 
     # The controllers memcg_stree test seems to cause us hangs and takes 900s