usb: dwc3: gadget: Fix IN endpoint max packet size allocation

usb: dwc3: gadget: Fix IN endpoint max packet size allocation

The current logic to assign the max packet limit for IN endpoints attempts
to take the default HW value and apply the optimal endpoint settings based
on it.  However, if the default value reports a TxFIFO size large enough
for only one max packet, it will divide the value and assign a smaller ep
max packet limit.

For example, if the default TxFIFO size fits 1024B, current logic will
assign 1024/3 = 341B to ep max packet size.  If function drivers attempt to
request for an endpoint with a wMaxPacketSize of 1024B (SS BULK max packet
size) then it will fail, as the gadget is unable to find an endpoint which
can fit the requested size.

Functionally, if the TxFIFO has enough space to fit one max packet, it will
be sufficient, at least when initializing the endpoints.

Fixes: d94ea5319813 ("usb: dwc3: gadget: Properly set maxpacket limit")
Cc: stable <stable@kernel.org>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Link: https://lore.kernel.org/r/20220523213948.22142-1-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>