of: unittest: initialize args before calling of_*parse_*()

of: unittest: initialize args before calling of_*parse_*()

Callers of of_irq_parse_one() blindly use the pointer args.np
without checking whether of_irq_parse_one() had an error and
thus did not set the value of args.np.  Initialize args to
zero so that using the format "%pOF" to show the value of
args.np will show "(null)" when of_irq_parse_one() has an
error.  This prevents the dereference of a random value.

Make the same fix for callers of of_parse_phandle_with_args()
and of_parse_phandle_with_args_map().

Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Alan Tull <atull@kernel.org>
Signed-off-by: Frank Rowand <frank.rowand@sony.com>