Something along the lines of pngversion.patch was merged upstream, so drop that
patch.
Also use the new trim_version() function for a future-proof SRC_URI.
(From OE-Core rev: 30b32addd189e7acce73965c9176227d5f392ab9)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>