Remove use of atmega328pb as some gcc versions do not recognise it.

Fixes BUG #552 -
    "Can't compile on MacOS Sonoma (Apple Silicon M1) from Homebrew".

Author: ga

tests/atmega328pb_jsys.c renamed to tests/atmega328_jsys.c

@@ -1,5 +1,5 @@
 /*
- * atmega328pb_jsys.c: a small demonstaration of using an illegal
+ * atmega328_jsys.c: a small demonstaration of using an illegal
  * instruction code to raise an IRQ and invoke a service from the
  * surrounding application.  In this case a simple sleep/wake.
  * The technique allows low-overhead simulation of busy-waiting.
@@ -12,7 +12,7 @@
 #include <avr/sleep.h>
 
 #include "avr_mcu_section.h"
-AVR_MCU(F_CPU, "atmega328pb");
+AVR_MCU(F_CPU, "atmega328");
 
 uint8_t count, ext_count;
 

tests/test_atmega328pb_jsys.c renamed to tests/test_atmega328_jsys.c

@@ -101,7 +101,7 @@ int main(int argc, char **argv) {
 	uint8_t  inner, outer;
 
 	tests_init(argc, argv);
-	avr = tests_init_avr("atmega328pb_jsys.axf");
+	avr = tests_init_avr("atmega328_jsys.axf");
 
 	avr_irq_register_notify(avr_get_core_irq(avr, AVR_CORE_BAD_OPCODE),
 							jsys_handler, avr);