Staging: android: fix up units in timed_gpio

The last build fix I did messed up the units of the sysfs file.

This puts them back to be milliseconds, like they originally were.

Thanks to Juha Motorsportcom for pointing this out.

Reported-by: Juha Motorsportcom <juha_motorsportcom@luukku.com>
Cc: Mike Lockwood <lockwood@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>