USB OTG: Add common data structure for Intel MID Platform (Langwell/Penwell)

This patch adds one new header file for the common data structure used in
Intel Penwell/Langwell MID Platform OTG Transceiver drivers. After switched
to the common data structure, Langwell/Penwell OTG Transceiver driver will
provide an unified interface to host/client driver.

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Hao Wu <hao.wu@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>