Input: pm8xxx-vibrator - correct VIB_MAX_LEVELS calculation

The output voltage is inclusive hence the max level calculation is
off-by-one-step. Correct it.

iWhile we are at it also add a define for the step size instead of
using the magic value.

Fixes: 11205bb ("Input: add support for pm8xxx based vibrator driver")
Signed-off-by: Fenglin Wu <[email protected]>
Reviewed-by: Dmitry Baryshkov <[email protected]>
Link: https://lore.kernel.org/r/20240412-pm8xxx-vibrator-new-design-v10-1-0ec0ad133866@quicinc.com
Signed-off-by: Dmitry Torokhov <[email protected]>

Author: Fenglin Wu

drivers/input/misc/pm8xxx-vibrator.c

@@ -13,7 +13,8 @@
 
 #define VIB_MAX_LEVEL_mV	(3100)
 #define VIB_MIN_LEVEL_mV	(1200)
-#define VIB_MAX_LEVELS		(VIB_MAX_LEVEL_mV - VIB_MIN_LEVEL_mV)
+#define VIB_PER_STEP_mV		(100)
+#define VIB_MAX_LEVELS		(VIB_MAX_LEVEL_mV - VIB_MIN_LEVEL_mV + VIB_PER_STEP_mV)
 
 #define MAX_FF_SPEED		0xff
 
@@ -117,10 +118,10 @@ static void pm8xxx_work_handler(struct work_struct *work)
 		vib->active = true;
 		vib->level = ((VIB_MAX_LEVELS * vib->speed) / MAX_FF_SPEED) +
 						VIB_MIN_LEVEL_mV;
-		vib->level /= 100;
+		vib->level /= VIB_PER_STEP_mV;
 	} else {
 		vib->active = false;
-		vib->level = VIB_MIN_LEVEL_mV / 100;
+		vib->level = VIB_MIN_LEVEL_mV / VIB_PER_STEP_mV;
 	}
 
 	pm8xxx_vib_set(vib, vib->active);