package/libsvg: remove package

This package is no longer maintained, no release since 2005, and it
has build issues as it uses too old XML APIs:

/home/thomas/projets/buildroot/output/host/bin/../aarch64-buildroot-linux-gnu/sysroot/usr/include/libxml2/libxml/SAX.h:18:4: warning: #warning "libxml/SAX.h is deprecated" [-Wcpp]
   18 |   #warning "libxml/SAX.h is deprecated"
      |    ^~~~~~~

svgint.h:42:9: error: unknown type name 'xmlParserCtxtPtr'
   42 | typedef xmlParserCtxtPtr svg_xml_parser_context_t;
      |         ^~~~~~~~~~~~~~~~

Fixes:

  https://autobuild.buildroot.net/results/895fdba2f3fcaa42aa93946f2532351d39b16647/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -591,7 +591,6 @@ F:	package/sunxi-boards/
 
 N:	Carsten Schoenert <c.schoenert@gmail.com>
 F:	package/libdvbsi/
-F:	package/libsvg/
 
 N:	Cédric Chépied <cedric.chepied@gmail.com>
 F:	package/znc/