sh: Don't profile return_address().

This adds return_address.c to the -pg exclusion list, as this is the
building block for CALLER_ADDRx we do not want to profile this.

Signed-off-by: Paul Mundt <[e-mail]>

arch/sh/kernel/Makefile

···
 CFLAGS_REMOVE_ftrace.o = -pg
 endif
 
+CFLAGS_REMOVE_return_address.o = -pg
+
 obj-y	:= debugtraps.o dumpstack.o idle.o io.o io_generic.o irq.o	\
 	   machvec.o nmi_debug.o process_$(BITS).o ptrace_$(BITS).o	\
 	   return_address.o						\