Add fit-dtb.blob* to .gitignore.

Support for compressed fit-dtb.blob was added in:

  commit 95f4bbd581cf ("lib: fdt: Allow LZO and GZIP DT compression in
  U-Boot")

Adjust .gitignore to also exclude compressed blobs.

Signed-off-by: Vagrant Cascadian <vagrant@reproducible-builds.org>
diff --git a/.gitignore b/.gitignore
index c2afcfb..d8b7b77 100644
--- a/.gitignore
+++ b/.gitignore
@@ -35,7 +35,7 @@
 #
 # Top-level generic files
 #
-fit-dtb.blob
+fit-dtb.blob*
 /MLO*
 /SPL*
 /System.map