USB: EHCI: make all debugging depend on CONFIG_DYNAMIC_DEBUG

The debugging facilities in ehci-dbg.c follow an uneven pattern.  Some
of them are protected by "#ifdef CONFIG_DYNAMIC_DEBUG" and some
aren't, presumably in the hope of having some of the debugging output
available in any configuration.

This leads to build problems when dynamic debugging isn't configured.
Rather than try to keep this complicated state of affairs, let's just
make everything dependent on CONFIG_DYNAMIC_DEBUG.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>