Add three macro to simplify the readability of big bit timing numbers:
  - CAN_KBPS: kilobits per second (one thousand)
  - CAN_MBPS: megabits per second (one million)
  - CAN_MHZ: megahertz per second (one million)
Example:
	u32 bitrate_max = 8 * CAN_MBPS;
	struct can_clock clock = {.freq = 80 * CAN_MHZ};
instead of:
	u32 bitrate_max = 
8000000;
	struct can_clock clock = {.freq = 
80000000};
Apply the new macro to driver/net/can/dev/bittiming.c.
Link: https://lore.kernel.org/r/20210306054040.76483-1-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
 
        if (bt->sample_point) {
                sample_point_nominal = bt->sample_point;
        } else {
-               if (bt->bitrate > 800000)
+               if (bt->bitrate > 800 * CAN_KBPS)
                        sample_point_nominal = 750;
-               else if (bt->bitrate > 500000)
+               else if (bt->bitrate > 500 * CAN_KBPS)
                        sample_point_nominal = 800;
                else
                        sample_point_nominal = 875;
 
 
 #define CAN_SYNC_SEG 1
 
+
+/* Kilobits and Megabits per second */
+#define CAN_KBPS 1000UL
+#define CAN_MBPS 1000000UL
+
+/* Megahertz */
+#define CAN_MHZ 1000000UL
+
 /*
  * struct can_tdc - CAN FD Transmission Delay Compensation parameters
  *