[ARM] tegra: fix one-shot support, register timer 3

one-shot mode was not reported to the kernel due to a spurious comma
operator

include the full-system IRQ header file and delete the local redefinitions;
the local redefinitions were incorrect for timers 3 and 4 (was 41 and 42,
should be 73 and 74)

switch the global event timer from hardware timer 1 to timer 3. tegra
multimedia firmware uses timers 1 and 2 as an event and watchdog timer
for the multimedia engine. timers 3 and 4 are available for OS usage.

Signed-off-by: Gary King <gking@nvidia.com>