arm64: debug: mark test_[bp,wp,ss] as noinline

Clang inlines some functions (like test_ss) which define global labels
in inline assembly (e.g., ss_start). This results in:

    arm/debug.c:382:15: error: invalid symbol redefinition
            asm volatile("ss_start:\n"
                         ^
    <inline asm>:1:2: note: instantiated into assembly here
            ss_start:
            ^
    1 error generated.

Fix these functions by marking them as "noinline".

Cc: Andrew Jones <drjones@redhat.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>