drm-shim: fix EOF case

Close input end of the pipe after data was written. Without this
fix I have seen a hang in sysfs_uevent_get(.., "OF_FULLNAME")
when key was not found.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

src/drm-shim/drm_shim.c

@@ -219,6 +219,7 @@ PUBLIC FILE *fopen(const char *path, const char *mode)
          pipe(fds);
          write(fds[1], file_overrides[i].contents,
                strlen(file_overrides[i].contents));
+         close(fds[1]);
          return fdopen(fds[0], "r");
       }
    }