MIPS, Perf-events: Work with the new PMU interface

This is the MIPS part of the following commits by Peter Zijlstra:

- a4eaf7f1
    perf: Rework the PMU methods

    Replace pmu::{enable,disable,start,stop,unthrottle} with
    pmu::{add,del,start,stop}, all of which take a flags argument.

    The new interface extends the capability to stop a counter while
    keeping it scheduled on the PMU. We replace the throttled state with
    the generic stopped state.

    This also allows us to efficiently stop/start counters over certain
    code paths (like IRQ handlers).

    It also allows scheduling a counter without it starting, allowing for
    a generic frozen state (useful for rotating stopped counters).

    The stopped state is implemented in two different ways, depending on
    how the architecture implemented the throttled state:

     1) We disable the counter:
        a) the pmu has per-counter enable bits, we flip that
        b) we program a NOP event, preserving the counter state

     2) We store the counter state and ignore all read/overflow events

For MIPSXX, the stopped state is implemented in the way of 1.b as above.

- 33696fc0
    perf: Per PMU disable

    Changes perf_disable() into perf_pmu_disable().

- 24cd7f54
    perf: Reduce perf_disable() usage

    Since the current perf_disable() usage is only an optimization,
    remove it for now. This eases the removal of the __weak
    hw_perf_enable() interface.

- b0a873eb
    perf: Register PMU implementations

    Simple registration interface for struct pmu, this provides the
    infrastructure for removing all the weak functions.

- 51b0fe39
    perf: Deconstify struct pmu

    sed -ie 's/const struct pmu\>/struct pmu/g' `git grep -l "const struct pmu\>"`

Reported-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Cc: ddaney@caviumnetworks.com
Patchwork: http://patchwork.linux-mips.org/patch/2012/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>