drivers: counter: stm32_timer: use "cc" interrupt if it exists

Currently, the STM32 TIM counter driver will always register itself as ISR
for interrupts[0] of the timer node. This works fine for timers which have
a single "global" interrupt but not for others (e.g., Advanced Timer) which
have separate IRQ lines for various events.

Borrow the pattern from PWM driver: use the "cc" interrupt if it exists on
timer node, otherwise use the "global" interrupt. If neither of those are
found, a build error is raised to ensure silent failures cannot occur.

Signed-off-by: Mathieu Choplain <mathieu.choplain@st.com>