gnu-efi: Use objcopy from GNU binutils with clang

llvm-objcopy reports errors which needs further investigations but
stick to binutils provided objcopy meanwhile

(From OE-Core rev: 5476ecaac46dfeefac9b4f2c9c18d5d57ab1ea0b)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-bsp/gnu-efi/gnu-efi_4.0.0.bb

@@ -22,6 +22,10 @@ SRCREV = "5ea320f0f01c8de8f9dd4e4e38a245608f0287dd"
 
 S = "${WORKDIR}/git"
 
+# llvm-objcopy fails
+# arm-poky-linux-gnueabi-llvm-objcopy: error: 't8.so': section '.dynstr' cannot be removed because it is referenced by the section '.dynamic'
+OBJCOPY:toolchain-clang = "${HOST_PREFIX}objcopy"
+
 inherit github-releases
 
 do_configure:linux-gnux32:prepend() {