xapp_xcompmgr: select xlib_libXrender

Fixes:
http://autobuild.buildroot.net/results/969/9690a67083f31070e27c95b053fc0fd389fd373a/



libXrender is added to _DEPENDENCIES, but not selected at the kconfig level.
While we're at it, sort the selects alphabetically and drop the double
libxfixes select.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>