[macppc] devel/clang-tools-extra: remove BROKEN

Hi,

Since i've set up BROKEN for this port, due to time wasted because it's
lacking consumers, rust has taken out many ports, the bootstrapped
guile2 now builds in a reasonable time, and even recently we're finally
free from Qt4.

I'm proposing to bring back clang-tools-extra. It builds fine [0] if
you wonder.

OK?

Charlène.

[0] https://bin.charlenew.xyz/clang-tools-extra-11.1.0p0.log


Index: Makefile
===================================================================
RCS file: /cvs/ports/devel/clang-tools-extra/Makefile,v
retrieving revision 1.16
diff -u -p -u -p -r1.16 Makefile
--- Makefile 18 May 2021 06:19:48 -0000 1.16
+++ Makefile 27 Jul 2021 18:42:43 -0000
@@ -9,7 +9,6 @@
# patches: rm patches/patch-*lld*

ONLY_FOR_ARCHS = ${LLVM_ARCHS}
-BROKEN-powerpc = no consumers on powerpc, save 25 build hours in bulks

COMMENT= Clang extra tools