usb:hsotg:samsung: Sending ZLP packet for IN EP0 transfers

This commit targets following scenarios for IN requests:

1. HOST requests e.g. 256B (which is a multiple of MPS = 64B).
Then NO ZLP shall be sent, since host expects exact number of bytes.

2. HOST requested 4096B, but our data for sending is 256B. In this
situation ZLP shall be send to tell HOST that no more data is available
and it shall not wait for more data. This prevents HOST from hanging.

Tested with:
- DFU gadget (various size of the sent data - also packet = MPS)
- Ethernet gadget (CDC and RNDIS)
- Multi Function Gadget (g_multi)

HW:
- Samsung's C210 Universal rev.0
- Samsung's C110 GONI

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>