usb: chipidea: remove flag CI_HDRC_REQUIRE_TRANSCEIVER

Now, USB PHY is mandatory for chipidea core, the flag
CI_HDRC_REQUIRE_TRANSCEIVER is useless.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>