Move .gitignore from drivers/md to lib/raid6

Another missing bit of the raid6 -> /lib move.

Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/lib/raid6/.gitignore b/lib/raid6/.gitignore
new file mode 100644
index 0000000..162beca
--- /dev/null
+++ b/lib/raid6/.gitignore
@@ -0,0 +1,4 @@
+mktables
+altivec*.c
+int*.c
+tables.c