usb: dwc2: gadget: fix TX FIFO size and address initialization

According to DWC2 documentation, DPTxFSize field of DPTXFSIZn register
is read only, which means that software cannot change FIFO size.

Register description says:
"The value of this register is the Largest Device Mode Periodic Tx Data
FIFO Depth (parameter OTG_TX_DPERIO_DFIFO_DEPTH_n), as specified during
coreConsultant configuration."

That means, that we have to setup only FIFO start addresses (DPTxFStAddr),
taking into account reset values of DPTxFSize.

Initialize FIFO start addresses properly and remove unneeded core related
to incorrect FIFO size initialization.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>