grub2: Drop unneeded code

We no longer export these variables into the environment so we no longer
need this code.

(From OE-Core rev: fd85639bf3092491123e8747e44e7b30648c85cf)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-bsp/grub/grub2.inc

@@ -63,10 +63,6 @@ BUILD_LDFLAGS = ""
 CFLAGS_append = " -Wno-error"
 
 do_configure_prepend() {
-	# The grub2 configure script uses variables such as TARGET_CFLAGS etc
-	# for its own purposes. Remove the OE versions from the environment to
-	# avoid conflicts.
-	unset TARGET_CPPFLAGS TARGET_CFLAGS TARGET_CXXFLAGS TARGET_LDFLAGS
 	( cd ${S}
 	${S}/autogen.sh )
 }