idpf: add support for SW triggered interrupts

idpf: add support for SW triggered interrupts

SW triggered interrupts are guaranteed to fire after their timer
expires, unlike Tx and Rx interrupts which will only fire after the
timer expires _and_ a descriptor write back is available to be processed
by the driver.

Add the necessary fields, defines, and initializations to enable a SW
triggered interrupt in the vector's dyn_ctl register.

Reviewed-by: Madhu Chittim <madhu.chittim@intel.com>
Signed-off-by: Joshua Hay <joshua.a.hay@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>