clocksource/mips-gic-timer: Stop checking cpu_has_counter

The cpu_has_counter macro indicates whether the current CPU has a
working coprocessor 0 count & compare registers, and has no bearing on
the GIC. Stop checking it.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: http://lkml.kernel.org/r/20160913165644.627-2-paul.burton@imgtec.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>