[POWERPC] Add files build to .gitignore

Mostly taken from corresponding Makefile's make-clean rule.

Tested by (cross)compiling for $ARCH PPC and POWERPC and checking
output of git-status.

Signed-off-by: Rutger Nijlunsing <git-commit@tux.tmfweb.nl>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/.gitignore b/arch/powerpc/.gitignore
new file mode 100644
index 0000000..a1a869c
--- /dev/null
+++ b/arch/powerpc/.gitignore
@@ -0,0 +1 @@
+include