MIPS: oprofile: Support for XLR/XLS processors

MIPS: oprofile: Support for XLR/XLS processors

Add support for XLR and XLS processors in MIPS Oprofile code. These
processors are multi-threaded and have two counters per core. Each
counter can track either all the events in the core (global mode),
or events in just one thread.

We use the counters in the global mode, and use only the first thread
in each core to handle the configuration etc.

Signed-off-by: Madhusudan Bhat <mbhat@netlogicmicro.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Patchwork: http://patchwork.linux-mips.org/patch/4471
Signed-off-by: John Crispin <blogic@openwrt.org>