expat: upgrade to 2.5.0

Release 2.5.0 Tue October 25 2022
        Security fixes:
  #616 #649 #650  CVE-2022-43680 -- Fix heap use-after-free after overeager
                    destruction of a shared DTD in function
                    XML_ExternalEntityParserCreate in out-of-memory situations.
                    Expected impact is denial of service or potentially
                    arbitrary code execution.

        Bug fixes:
       #612 #645  Fix curruption from undefined entities
       #613 #654  Fix case when parsing was suspended while processing nested
                    entities
  #616 #652 #653  Stop leaking opening tag bindings after a closing tag
                    mismatch error where a parser is reset through
                    XML_ParserReset and then reused to parse
            #656  CMake: Fix generation of pkg-config file
            #658  MinGW|CMake: Fix static library name

        Other changes:
            #663  Protect header expat_config.h from multiple inclusion
            #666  examples: Make use of XML_GetBuffer and be more
                    consistent across examples
            #648  Address compiler warnings
       #667 #668  Version info bumped from 9:9:8 to 9:10:8;
                    see https://verbump.de/

 for what these numbers do

Includes a fix for CVE-2022-43680.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit a257a674)
Signed-off-by: Steve Sakoman <steve@sakoman.com>