This change adds a new TMU function timer_spinwait() which waits for a
timer to raise its UNF flag. This makes it possible to wait even when
interrupts are disabled.
This is used by the new CPG function sleep_us_spin() which waits for a
given delay without using interrupts. This is currently used in SPU
initialization.
This commit minimally changes the signature of timer_setup() to greatly
simplify timer management, allowing to user to let the library choose
available timers dynamically depending on the settings.
Lephe
lephe