Nissan: Added ProPilot brake pressure signal (#2137)

* Added brake pressure signal

* Add brake active signal

Author: gncnpk

opendbc/dbc/generator/nissan/_nissan_common.dbc

@@ -58,6 +58,10 @@ BO_ 689 PROPILOT_HUD: 8 XXX
  SG_ unknown55 : 55|8@0+ (1,0) [0|63] "" XXX
  SG_ unknown59 : 59|4@0+ (1,0) [0|15] "" XXX
 
+BO_ 451 PROPILOT_BRAKE: 8 XXX
+ SG_ BRAKE_PRESSURE : 5|9@0+ (1,0) [0|511] "" XXX
+ SG_ BRAKE_ACTIVE : 47|1@0+ (1,0) [0|1] "" XXX
+
 BO_ 783 CRUISE_STATE: 3 XXX
  SG_ CRUISE_ENABLED : 3|1@0+ (1,0) [0|1] "" XXX