tracing: Allow tracepoint-update.c to work with modules

tracing: Allow tracepoint-update.c to work with modules

In order for tracepoint-update.c to work with modules, it cannot error out
if both "__tracepoint_check" and "__tracepoints_strings" are not found.
When enabled, the vmlinux.o may be required to have both, but modules only
have these sections if they have tracepoints. Modules without tracepoints
will not have either. They should not fail to build because of that.

If one section exists the other one should too. Note, if a module defines
a tracepoint but doesn't use any, it can cause this to fail.

Add a new "--module" parameter to tracepoint-update to be used when
running on module code. It will not error out if this is set and both
sections are missing. If this is set, and only the "__tracepoint_check"
section is missing, it means the module has defined tracepoints but none
of them are used. In that case, it prints a warning that the module has
only unused tracepoints and exits normally to not fail the build.

If the "__tracepoint_check" section exists but not the
"__tracepoint_strings", then that is an error and should fail the build.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas.schier@linux.dev>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/20251022004453.255696445@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>