target/avr: Fix handling of interrupts above 33.

This commit addresses a bug in the AVR interrupt handling code.
The modification involves replacing the usage of the ctz32 function
with ctz64 to ensure proper handling of interrupts above 33 in the AVR
target.

Previously, timers 3, 4, and 5 interrupts were not functioning correctly
because most of their interrupt vectors are numbered above 33.

Signed-off-by: Lucas Dietrich <ld.adecy@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael Rolnik <mrolnik@gmail.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
(Mjt: updated subject line to have subsytem prefix)

target/avr/helper.c

@@ -52,7 +52,7 @@ bool avr_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
     }
     if (interrupt_request & CPU_INTERRUPT_HARD) {
         if (cpu_interrupts_enabled(env) && env->intsrc != 0) {
-            int index = ctz32(env->intsrc);
+            int index = ctz64(env->intsrc);
             cs->exception_index = EXCP_INT(index);
             avr_cpu_do_interrupt(cs);
 
@@ -79,7 +79,7 @@ void avr_cpu_do_interrupt(CPUState *cs)
     if (cs->exception_index == EXCP_RESET) {
         vector = 0;
     } else if (env->intsrc != 0) {
-        vector = ctz32(env->intsrc) + 1;
+        vector = ctz64(env->intsrc) + 1;
     }
 
     if (avr_feature(env, AVR_FEATURE_3_BYTE_PC)) {