Staging: gdm724x: Change spaces to tabs

This patch fixes the following checkpatch.pl warning in gdm_usb.c:
WARNING: suspect code indent for conditional statements (8, 12)
Signed-off-by: Mart Lubbers <mart@martlubbers.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>