Add support utils for tracing

Following patch adds a userspace util genprof
which is able to convert the console printed
traces to gmon.out file used by gprof & friends.
The log2dress will replace the adresses in logfile
with a line numbers.

Change-Id: I9f716f3ff2522a24fbc844a1dd5e32ef49b540c5
Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Reviewed-on: http://review.coreboot.org/179
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

util/genprof/README

@@ -0,0 +1,31 @@
+Function tracing
+----------------
+
+Enable CONFIG_TRACE in debug menu. Run the compiled image on target. You will get
+a log with a lot of lines like:
+
+...
+~0x001072e8(0x00100099)
+~0x00108bc0(0x0010730a)
+...
+
+First address is address of function which was just entered, the second address
+is address of functions which call that.
+
+You can use the log2dress to dress the log again:
+
+...
+src/arch/x86/lib/c_start.S:85 calls /home/ruik/coreboot/src/boot/selfboot.c:367
+/home/ruik/coreboot/src/boot/selfboot.c:370 calls /home/ruik/coreboot/src/devices/device.c:325
+...
+
+Alternatively, you can use genprof to generate a gmon.out file, which can be used
+by gprof to show the call traces. You will need to install uthash library to compile
+that.
+
+Great use is:
+
+make
+./genprof /tmp/yourlog ;  gprof ../../build/coreboot_ram |  ./gprof2dot.py -e0 -n0 | dot -Tpng -o output.png
+
+Which generates a PNG with a call graph.