how to interface SPI with altera using state machines!?

It can basically work with a state machine. In my opinion, using a shift register and a bit counter is a more simple solution. See attached an example sending 24 bit data with SPI mode 1. Consider that your chip needs 16 bits and SPI mode 0. The code is generating a SPICLK of half the system clock, which should be suitable for most newer chips.