arm-cci: Add aliases for PMU events

Each CCI model have different event/source codes and formats. This
patch exports this information via the sysfs, which includes the
aliases for the events. The aliases are listed by 'perf list', helping
the users to specify the name of the event instead of the binary
config values.

Each event alias must accompany the 'source' code except for the
following cases :

1) CCI-400 - cycles event, doesn't relate to an interface.
2) CCI-500 - Global events to the CCI. (Fixed source code = 0xf)

Each CCI model provides two sets of attributes(format and event),
which are dynamically populated before registering the PMU, to
allow for the appropriate information.

Cc: Punit Agrawal <punit.agrawal@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>