usb: dwc2: host: Rename MAX_DMA_DESC_SIZE to HOST_DMA_NBYTES_LIMIT

Rename MAX_DMA_DESC_SIZE to HOST_DMA_NBYTES_LIMIT as it stores value of
host DMA descriptor transfer bytes' limit. Values are different in case
of gadget DMA descriptors.

Signed-off-by: Vahram Aharonyan <vahrama@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>