[MIPS] Ignore vmlinux.lds generated files

This patch adds the proper .gitignore file to ignore vmlinux.lds generated
in arch/mips/kernel/.

Signed-off-by: Florian Fainelli <florian.fainelli@telecomint.eu>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/.gitignore b/arch/mips/kernel/.gitignore
new file mode 100644
index 0000000..c5f676c
--- /dev/null
+++ b/arch/mips/kernel/.gitignore
@@ -0,0 +1 @@
+vmlinux.lds