mx7: Fix the get_cpu_speed_grade_hz() return values

According to the MX7D fuse map the following speed grades are available:

800  MHz
500  MHz
1000 MHz
1200 MHz

So simply return the real frequency that corresponds to the speed grade.

With this change we see on boot:

CPU:   Freescale i.MX7D rev1.2 1000 MHz (running at 792 MHz)

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>

arch/arm/cpu/armv7/mx7/soc.c

@@ -120,11 +120,11 @@ u32 get_cpu_speed_grade_hz(void)
 
 	switch(val) {
 	case OCOTP_TESTER3_SPEED_800MHZ:
-		return 792000000;
+		return 800000000;
 	case OCOTP_TESTER3_SPEED_500MHZ:
 		return 500000000;
 	case OCOTP_TESTER3_SPEED_1GHZ:
-		return 996000000;
+		return 1000000000;
 	}
 	return 0;
 }