vbo: improve the code style by adjust the preprocessing c code directives

vbo: improve the code style by adjust the preprocessing c code directives

Brian Paul review suggestion: there's more macro use here than necessary.
Removed and redefine some #define preprocessing directives.
Removed the directive input parameter 'T' .
No functional changes.

Signed-off-by: Marius Predut <marius.predut@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com>