timestamps: Switch from tsc_t to uint64_t

Cherry-pick from chromium and adjusted for added boards
and changed directory layout for arch/arm.

Timestamp implementation for ARMv7

Abstract the use of rdtsc() and make the timestamps
uint64_t in the generic code.

The ARM implementation uses the monotonic timer.

Original-Signed-off-by: Stefan Reinauer <reinauer@google.com>

TEST=See cbmem print timestamps

Original-Change-Id: Id377ba570094c44e6895ae75f8d6578c8865ea62
Original-Reviewed-on: https://gerrit.chromium.org/gerrit/63793
(cherry-picked from commit cc1a75e059020a39146e25b9198b0d58aa03924c)

Change-Id: Ic51fb78ddd05ba81906d9c3b35043fa14fbbed75
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/8020
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
22 files changed