parisc: Fix ftrace function tracer

Fix the FTRACE function tracer for 32- and 64-bit kernel.
The former code was horribly broken.

Reimplement most coding in assembly and utilize optimizations, e.g. put
mcount() and ftrace_stub() into one L1 cacheline.

Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index 965a099..75cb451 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -62,9 +62,7 @@
 
 # Without this, "ld -r" results in .text sections that are too big
 # (> 0x40000) for branches to reach stubs.
-ifndef CONFIG_FUNCTION_TRACER
-  cflags-y	+= -ffunction-sections
-endif
+cflags-y	+= -ffunction-sections
 
 # Use long jumps instead of long branches (needed if your linker fails to
 # link a too big vmlinux executable). Not enabled for building modules.