Add fdtget utility to read property values from a device tree

This simply utility makes it easy for scripts to read values from the device
tree. It is written in C and uses the same libfdt as the rest of the dtc
package.

What is it for:
- Reading fdt values from scripts
- Extracting fdt information within build systems
- Looking at particular values without having to dump the entire tree

To use it, specify the fdt binary file on command line followed by a list of
node, property pairs. The utility then looks up each node, finds the property
and displays the value.

Each value is printed on a new line.

fdtget tries to guess the type of each property based on its contents. This
is not always reliable, so you can use the -t option to force fdtget to decode
the value as a string, or byte, etc.

To read from stdin, use - as the file.

Usage:
	fdtget <options> <dt file> [<node> <property>]...
Options:
	-t <type>	Type of data
	-h		Print this help

<type>	s=string, i=int, u=unsigned, x=hex
	Optional modifier prefix:
		hh or b=byte, h=2 byte, l=4 byte (default)

Signed-off-by: Simon Glass <sjg@chromium.org>

Makefile

@@ -110,6 +110,7 @@ include Makefile.utils
 BIN += convert-dtsv0
 BIN += dtc
 BIN += fdtdump
+BIN += fdtget
 
 SCRIPTS = dtdiff
 
@@ -120,6 +121,7 @@ ifneq ($(DEPTARGETS),)
 -include $(DTC_OBJS:%.o=%.d)
 -include $(CONVERT_OBJS:%.o=%.d)
 -include $(FDTDUMP_OBJS:%.o=%.d)
+-include $(FDTGET_OBJS:%.o=%.d)
 endif
 
 
@@ -180,6 +182,8 @@ convert-dtsv0: $(CONVERT_OBJS)
 
 fdtdump:	$(FDTDUMP_OBJS)
 
+fdtget:	$(FDTGET_OBJS) $(LIBFDT_archive)
+
 
 #
 # Testsuite rules