coresight tmc: Add helpers for accessing 64bit registers

coresight tmc: Add helpers for accessing 64bit registers

Coresight TMC splits 64bit registers into a pair of 32bit registers
(e.g DBA, RRP, RWP). Provide helpers to read/write to these registers.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>