irq/generic-chip: Don't replace domain's name

When generic irq chips are allocated for an irq domain the domain name is
set to the irq chip name. That was done to have named domains before the
recent changes which enforce domain naming were done.

Since then the overwrite causes a memory leak when the domain name is
dynamically allocated and even worse it would cause the domain free code to
free the wrong name pointer, which might point to a constant.

Remove the name assignment to prevent this.

Fixes: d59f6617

 ("genirq: Allow fwnode to carry name information only")
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20170928043731.4764-1-jeffy.chen@rock-chips.com