ice: Update comment regarding the ITR_GRAN_S

Since the driver now hard codes the ITR granularity to 2 us in the
GLINT_CTL register the comment next to ITR_GRAN_S needs to be updated.
Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ice/ice_txrx.h

@@ -128,7 +128,7 @@ enum ice_rx_dtype {
 #define ICE_ITR_DYNAMIC	0x8000  /* used as flag for itr_setting */
 #define ITR_IS_DYNAMIC(setting) (!!((setting) & ICE_ITR_DYNAMIC))
 #define ITR_TO_REG(setting)	((setting) & ~ICE_ITR_DYNAMIC)
-#define ICE_ITR_GRAN_S		1	/* Assume ITR granularity is 2us */
+#define ICE_ITR_GRAN_S		1	/* ITR granularity is always 2us */
 #define ICE_ITR_GRAN_US		BIT(ICE_ITR_GRAN_S)
 #define ICE_ITR_MASK		0x1FFE	/* ITR register value alignment mask */
 #define ITR_REG_ALIGN(setting)	__ALIGN_MASK(setting, ~ICE_ITR_MASK)