kernel: use proper macro to declare extern interrupt stacks

The z_interrupt_stacks was declared extern in the kernel internal
header file using the same macro which defines the same stack
array but with an added "extern" in front. This macro adds
alignment and section attribute which are actually not the same
as the actual stack array defined in kernel/init.c. The section
name used in the section attribute contains the file name where
the stack array is defined or extern declared. So the same
symbol, in this case z_interrupt_stacks, has different
attributes in two places, and GCC 11 starts to complain about
this. So use the newly introduced macro to extern declare
the stack array without adding/replacing any symbol attributes.

Signed-off-by: Daniel Leung <[email protected]>

kernel/include/kernel_internal.h

@@ -152,7 +152,7 @@ extern struct k_thread z_main_thread;
 #ifdef CONFIG_MULTITHREADING
 extern struct k_thread z_idle_threads[CONFIG_MP_NUM_CPUS];
 #endif
-extern K_KERNEL_STACK_ARRAY_DEFINE(z_interrupt_stacks, CONFIG_MP_NUM_CPUS,
+K_KERNEL_PINNED_STACK_ARRAY_EXTERN(z_interrupt_stacks, CONFIG_MP_NUM_CPUS,
 				   CONFIG_ISR_STACK_SIZE);
 
 #ifdef CONFIG_GEN_PRIV_STACKS