linux/device.h: use DYNAMIC_DEBUG_BRANCH in dev_dbg_ratelimited

linux/device.h: use DYNAMIC_DEBUG_BRANCH in dev_dbg_ratelimited

Patch series "various dynamic_debug patches", v4.

This started as an experiment to see how hard it would be to change the
four pointers in struct _ddebug into relative offsets, a la
CONFIG_GENERIC_BUG_RELATIVE_POINTERS, thus saving 16 bytes per pr_debug
site (and thus exactly making up for the extra space used by the
introduction of jump labels in 9049fc74).  I stumbled on a few things
that are probably worth fixing regardless of whether that goal is deemed
worthwhile.

Back at v3 (in November), I redid the implementation on top of the fancy
new asm-macros stuff.  Luckily enough, v3 didn't get picked up, since
the asm-macros were backed out again.  I still want to do the
relative-pointers thing eventually, but we're close to the merge window
opening, so here's just most of the "incidental" patches, some of which
also serve as preparation for the relative pointers.

This patch (of 4):

dev_dbg_ratelimited tests the dynamic debug descriptor the old-fashioned
way, and doesn't utilize the static key/jump label implementation when
CONFIG_JUMP_LABEL is set.  Use the DYNAMIC_DEBUG_BRANCH which is defined
appropriately.

Link: http://lkml.kernel.org/r/20190212214150.4807-2-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Jason Baron <jbaron@akamai.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>