spi_qsd: chip select doesn't assert for every 4k bytes

If infinite mode is not supported, chip select goes
high after every 4k bytes. Make sure the same behavior
does not happen on targets that support infinite mode.

CRs-Fixed: 361961
Change-Id: I5cfea96202718214a8edd060e06fbb7fb2fa90a2
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>