phpinfo() is an internal php command so you cannot change its output.
Ofcourse php is open source so you could make any changes yourself (in your case comment out a few lines in ext/standard/info.c) and recompile php. But i don't think many of us would want to do this if it means changing sourcecode and recompiling php.
There are some things you can hide though. For example, to hide the apache version information you could set "ServerSignature Off" and add "ServerTokens ProductOnly" in httpd.conf (info)
To hide some php information set "expose_php = Off" in php.ini.
You can even disable the phpinfo function completely if you want by adding phpinfo to the "disable_functions" line in php.ini