MIPS: Replace setup_irq() by request_irq()

request_irq() is preferred over setup_irq(). Invocations of setup_irq()
occur after memory allocators are ready.

Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.

Hence replace setup_irq() by request_irq().

remove_irq() has been replaced by free_irq() as well.

There were build error's during previous version, couple of which was
reported by kbuild test robot <lkp@intel.com> of which one was reported
by Thomas Bogendoerfer <tsbogend@alpha.franken.de> as well. There were a
few more issues including build errors, those also have been fixed.

[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Fork loongson2ef from loongson64

As later model of GSx64 family processors including 2-series-soc have
similar design with initial loongson3a while loongson2e/f seems less
identical, we separate loongson2e/f support code out of mach-loongson64
to make our life easier.

This patch contains mostly file moving works.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
[paulburton@kernel.org: Squash in the MAINTAINERS updates]
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: paul.burton@mips.com