ftrace: allow architectures to specify ftrace compile options

If the kernel is compiled with function tracer support the -pg compile option
is passed to gcc to generate extra code into the prologue of each function.

This patch replaces the "open-coded" -pg compile flag with a CC_FLAGS_FTRACE
makefile variable which architectures can override if a different option
should be used for code generation.

Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --cc Makefile
Simple merge

diff --cc kernel/Makefile
Simple merge

diff --cc kernel/events/Makefile
Simple merge

diff --cc kernel/locking/Makefile
Simple merge

diff --cc kernel/sched/Makefile
Simple merge

diff --cc kernel/trace/Makefile
Simple merge

diff --cc lib/Makefile
Simple merge

diff --cc scripts/Makefile.build
Simple merge