pr_debug() can now result in code being generated even when #DEBUG
is not defined. That's not really desirable in the ftrace code
which we want to be snappy.

With CONFIG_DYNAMIC_DEBUG=y:

size before:
   text	   data	    bss	    dec	    hex	filename
   3334	    672	      4	   4010	    faa	arch/powerpc/kernel/ftrace.o

size after:
   text	   data	    bss	    dec	    hex	filename
   2616	    360	      4	   2980	    ba4	arch/powerpc/kernel/ftrace.o
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>