binderfs: add gitignore for generated sample program

Let's keep "git status" happy and quiet.

Fixes: 9762dc1432e1 ("samples: add binderfs sample program
Fixes: fca5e94921d5 ("samples: binderfs: really compile this sample and fix build issues")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Changed files
+1
samples
binderfs
+1
samples/binderfs/.gitignore
··· 1 + binderfs_example