ARM: pmu: remove arm_pmu_type enumeration

The arm_pmu_type enumeration was initially introduced to identify
different PMU types in the system, the usual one being that on the CPU
(ARM_PMU_DEVICE_CPU). With the removal of the PMU reservation code and
the introduction of devicetree bindings for the CPU PMU, the enumeration
is no longer required.

This patch removes the enumeration and updates the various CPU PMU
platform devices so that they no longer pass an .id field referring
to identify the PMU type.

Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Pawel Moll <pawel.moll@arm.com>
Acked-by: Jon Hunter <jon-hunter@ti.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jiandong Zheng <jdzheng@broadcom.com>
Signed-off-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
[will: cosmetic edits and actual removal of the enum type]
Signed-off-by: Will Deacon <will.deacon@arm.com>