Revert "usb: chipidea: remove duplicate dev_set_drvdata for host_start"

This reverts commit 14b4099c074f2ddf4d84b22d370170e61b527529

It moved platform_set_drvdata(pdev, ci) before hcd is created,
and the hcd will assign itself as ci controller's drvdata during
the hcd creation function (in usb_create_shared_hcd), so it
overwrites the real ci's drvdata which we want to use.

So, if the controller is at host mode, the system suspend
API will get the wrong struct ci_hdrc pointer, and cause the
oops.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
usb: chipidea: udc: return immediately if re-enable non-empty endpoint

Some gadget driver (like uac1) will try to enable endpoint again even
the ep is not empty, it will cause the ep reset again and may affect
the dTD list which has already queued.

It returns -EBUSY immediately, and indicate the endpoint is in use.
In this way, the ep's behavior will not be affected, and the gadget
driver is also notified.

Cc: Xuebing Wang <xbing6@gmail.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
usb: chipidea: imx: using common platform flag directly

It is meaningless the glue layer driver has its own platform flag
which is the same meaning with common platform flag.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
usb: chipidea: usbmisc_imx: delete clock information

All imx usb controller's non core registers uses the same clock gate with
core registers, the usbmisc_imx is the library for imx glue driver, the
glue keeps clock on when it calls usbmisc_imx API to change non-core register.

Besides, we will support runtime pm in the future, it also needs to
close this clock when the usb is not in use.

Philipp Zabel also verifies it at imx6q platform, see
http://www.spinics.net/lists/linux-usb/msg118491.html

Cc: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
usb: chipidea: imx: simplify the usbmisc callers

Move struct imx_usbmisc_data NULL pointer judgement from caller to
each API, it can simplify the caller.

Signed-off-by: Peter Chen <peter.chen@freescale.com>