irqchip/mips-gic: Remove population of irq domain names

Since commit d59f6617 ("genirq: Allow fwnode to carry name
information only") the irqdomain core sets the names of irq domains.
When the name is allocated the new IRQ_DOMAIN_NAME_ALLOCATED flag is
set. Replacing the allocated name with a constant one is not a good
idea, since calling the new irq_domain_update_bus_token() API, added to
the MIPS GIC driver by commit 96f0d93a ("irqchip/MSI: Use
irq_domain_update_bus_token instead of an open coded access") will
attempt to kfree the pointer, and result in a kernel OOPS.

Fix this by removing the names, now that they are set by the irqdomain
core. This effectively reverts commit 21c57fd1 ("irqchip/mips-gic:
Populate irq_domain names").

Fixes: d59f6617 ("genirq: Allow fwnode to carry name information only")
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-mips@linux-mips.org
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1500363561-32213-1-git-send-email-matt.redfearn@imgtec.com