package/dtc: bump to version v1.5.0

Upstream now optionally supports a yaml output format, and support is
detected through pkg-config. It has not been added as a dependency but
could in the future if someone asks for it.

Patches applied upstream:

  - Kill bogus TYPE_BLOB marker type
  - checks: fix simple-bus compatible matching

New patch:

 - Makefile: Add EXTRA_CFLAGS variable

The new patch is required to correctly add buildroot's cflags. The
existing packaging was overwriting those set by the package's makefile,
which was breaking the yaml detection.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>