ARM: 9303/1: kprobes: avoid missing-declaration warnings

checker_stack_use_t32strd() and kprobe_handler() can be made static since
they are not used from other files, while coverage_start_registers()
and __kprobes_test_case() are used from assembler code, and just need
a declaration to avoid a warning with the global definition.

arch/arm/probes/kprobes/checkers-common.c:43:18: error: no previous prototype for 'checker_stack_use_t32strd'
arch/arm/probes/kprobes/core.c:236:16: error: no previous prototype for 'kprobe_handler'
arch/arm/probes/kprobes/test-core.c:723:10: error: no previous prototype for 'coverage_start_registers'
arch/arm/probes/kprobes/test-core.c:918:14: error: no previous prototype for '__kprobes_test_case_start'
arch/arm/probes/kprobes/test-core.c:952:14: error: no previous prototype for '__kprobes_test_case_end_16'
arch/arm/probes/kprobes/test-core.c:967:14: error: no previous prototype for '__kprobes_test_case_end_32'

Fixes: 6624cf65 ("ARM: kprobes: collects stack consumption for store instructions")
Fixes: 454f3e13 ("ARM/kprobes: Remove jprobe arm implementation")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>