Merge pull request #9921 from cladmi/pr/cleanup/pba/mcpu

pba-d-01-kw2x: remove duplicate MCPU

boards/pba-d-01-kw2x/Makefile.include

@@ -6,8 +6,6 @@ export CPU = kinetis
 # cpu if needed.
 export CPU_MODEL ?= mkw21d256vha5
 
-export MCPU = cortex-m4
-
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyACM0
 PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))