usb:udc:samsung: Allow burst transfers for non EP0 endpints

This patch removed obscure restriction on the HW setting of DMA transfers.
Before this change each transaction sent up to 512 bytes (with packet count
equal to 1) for non EP0 transfer.

Now it is possible to setup DMA transaction up to DMA_BUFFER_SIZE.

Test condition
- test HW + measurement: Trats - Exynos4210 rev.1
- test HW Trats2 - Exynos4412 rev.1
400 MiB compressed rootfs image download with `thor 0 mmc 0`

Measurement:
Transmission speed: 20.74 MiB/s

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Cc: Marek Vasut <marex@denx.de>