USB: gadget: u_bam: Don't set length for TX endless req for USB2

Currently driver is setting endless request length for USB IN endpoint
for USB2 controller case. For USB2 controller, length shouldn't be set
to 32KB, otherwise BAM2BAM connection will fail. Hence fix the issue by
not setting endless request length for USB2.

Change-Id: I1da72da866ac4e9007c3d57545978111031de653
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>