clocksource: arm_arch_timer: add a new enum for spi type

clocksource: arm_arch_timer: add a new enum for spi type

BugLink: http://bugs.launchpad.net/bugs/1688114
This patch add a new enum "arch_timer_spi_nr" and use it in the driver.
Just for code's readability, no functional change.

Signed-off-by: Fu Wei <fu.wei@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
(cherry picked from commit 097cd143dd871bfceacf4ed252b177cf515a1888)
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>