Sync to upstream dtc commit 0931cea3ba20 ("dtc: fdtdump: check fdt if
not in scanning mode"). In particular, this pulls in dtc overlay
support.

This adds the following commits from upstream:

f88865469b65 dtc: Fix memory leak in character literal parsing
00fbb8696b66 Rename boot_info
1ef86ad2c24f dtc: Clean up /dts-v1/ and /plugin/ handling in grammar
e3c769aa9c16 dtc: Don't always generate __symbols__ for plugins
c96cb3c0169e tests: Don't use -@ on plugin de/recompile tests
66381538ce24 tests: Remove "suppression of fixups" tests
ba765b273f0f tests: Clarify dtc overlay tests
6ea8cd944fcd tests: More thorough tests of libfdt overlay application without dtc
7d8ef6e1db97 tests: Correct fdt handling of overlays without fixups and base trees without symbols
b4dc0ed8b127 tests: Fix double expansion bugs in test code
3ea879dc0c8f tests: Split overlay tests into those with do/don't exercise dtc plugin generation
47b4d66a2f11 tests: Test auto-alias generation on base tree, not overlay
72e1ad811523 tests: Make overlay/plugin tests unconditional
e7b3c3b5951b tests: Add overlay tests
9637e3f772a9 tests: Add check_path test
20f29d8d41f6 dtc: Plugin and fixup support
a2c92cac53f8 dtc: Document the dynamic plugin internals
8f70ac39801d checks: Pass boot_info instead of root node
ea10f953878f libfdt: add missing errors to fdt_strerror()
daa75e8fa594 libfdt: fix fdt_stringlist_search()
e28eff5b787a libfdt: fix fdt_stringlist_count()
ae97c7722840 tests: overlay: Rename the device tree blobs to be more explicit
96162d2bd9cb tests: overlay: Add test suffix to the compiled blobs
5ce8634733b7 libfdt: Add fdt_overlay_apply to the exported symbols
804a9db90ad2 fdt: strerr: Remove spurious BADOVERLAY
e8c3a1a493fa tests: overlay: Move back the bad fixup tests
7a72d89d3f81 libfdt: overlay: Fix symbols and fixups nodes condition
cabbaa972cdd libfdt: overlay: Report a bad overlay for mismatching local fixups
deb0a5c1aeaa libfdt: Add BADPHANDLE error string
7b7a6be9ba15 libfdt: Don't use 'index' as a local variable name
aea8860d831e tests: Add tests cases for the overlay code
0cdd06c5135b libfdt: Add overlay application function
39240cc865cf libfdt: Extend the reach of FDT_ERR_BADPHANDLE
4aa3a6f5e6d9 libfdt: Add new errors for the overlay code
6d1832c9e64b dtc: Remove "home page" link
45fd440a9561 Fix some typing errors in libfdt.h and livetree.c
a59be4939c13 Merge tag 'v1.4.2'
a34bb721caca dtc: Fix assorted problems in the testcases for the -a option
874f40588d3e Implement the -a option to pad dtb aligned
ec02b34c05be dtc: Makefile improvements for release uploading
1ed45d40a137 dtc: Bump version to 1.4.2
36fd7331fb11 libfdt: simplify fdt_del_mem_rsv()
d877364e4a0f libfdt: Add fdt_setprop_inplace_namelen_partial
3e9037aaad44 libfdt: Add fdt_getprop_namelen_w
84e0e1346c68 libfdt: Add max phandle retrieval function
d29126c90acb libfdt: Add iterator over properties
902d0f0953d0 libfdt: Add a subnodes iterator macro
c539075ba8ba fdtput.c: Fix memory leak.
f79ddb83e185 fdtget.c: Fix memory leak
1074ee54b63f convert-dtsv0-lexer.l: fix memory leak
e24d39a024e6 fdtdump.c: make sure size_t argument to memchr is always unsigned.
44a59713cf05 Remove unused srcpos_dump() function
cb9241ae3453 DTC: Fix memory leak on flatname.
1ee0ae24ea09 Simplify check field and macro names
9d97527a8621 Remove property check functions
2e709d158e11 Remove tree check functions
c4cb12e193e3 Alter grammar to allow multiple /dts-v1/ tags
d71d25d76012 Use xasprintf() in srcpos
9dc404958e9c util: Add xasprintf portable asprintf variant
beef80b8b55f Correct a missing space in a fdt_header cast
68d43cec1253 Correct line lengths in libfdt.h
b0dbceafd49a Correct space-after-tab in libfdt.h
Signed-off-by: Rob Herring <robh@kernel.org>