Staging: w35und: simplify error handling in wb35_hw_init()

Impact: cleanup

Change hal_init_hardware() to return an error code rather than a boolean
to simplify error handling in wb35_hw_init().

Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>