spi: spi_qsd: Don't restrict first transfer in FIFO mode

In FIFO mode before putting the core in run state the driver currently
only writes a word of data if the payload size is more than the FIFO
size.
Instead always write FIFO worth of data before moving the core to
run state.

Change-Id: I47db9f66c95846dbff882f631b915655c33c3d55
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
Signed-off-by: Mukesh Kumar Savaliya <msavaliy@codeaurora.org>