USB: EHCI: Cleanup and rewrite ehci_vdgb().

The vdbg macro is not used anywhere so it can be removed.

With pre-release GCC-4.6, there are several complaints of variables
that are 'set but not used' caused by the ehci_vdbg() macro expanding
to something that does not contain any of its arguments.  We can quiet
this warning by rewriting ehci_vdbg() as a variadic static inline that
does nothing.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>