Fix target ARM processor (-mcpu) of STM32L0

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>

Author: fpistm

boards.txt

@@ -181,7 +181,7 @@ Nucleo_64.menu.pnum.NUCLEO_L053R8=Nucleo L053R8
 Nucleo_64.menu.pnum.NUCLEO_L053R8.node=NODE_L053R8
 Nucleo_64.menu.pnum.NUCLEO_L053R8.upload.maximum_size=65536
 Nucleo_64.menu.pnum.NUCLEO_L053R8.upload.maximum_data_size=8192
-Nucleo_64.menu.pnum.NUCLEO_L053R8.build.mcu=cortex-m0
+Nucleo_64.menu.pnum.NUCLEO_L053R8.build.mcu=cortex-m0plus
 Nucleo_64.menu.pnum.NUCLEO_L053R8.build.board=NUCLEO_L053R8
 Nucleo_64.menu.pnum.NUCLEO_L053R8.build.series=STM32L0xx
 Nucleo_64.menu.pnum.NUCLEO_L053R8.build.product_line=STM32L053xx
@@ -244,7 +244,7 @@ Nucleo_32.menu.pnum.NUCLEO_L031K6=Nucleo L031K6
 Nucleo_32.menu.pnum.NUCLEO_L031K6.node=NODE_L031K6
 Nucleo_32.menu.pnum.NUCLEO_L031K6.upload.maximum_size=32768
 Nucleo_32.menu.pnum.NUCLEO_L031K6.upload.maximum_data_size=8192
-Nucleo_32.menu.pnum.NUCLEO_L031K6.build.mcu=cortex-m0
+Nucleo_32.menu.pnum.NUCLEO_L031K6.build.mcu=cortex-m0plus
 Nucleo_32.menu.pnum.NUCLEO_L031K6.build.board=NUCLEO_L031K6
 Nucleo_32.menu.pnum.NUCLEO_L031K6.build.series=STM32L0xx
 Nucleo_32.menu.pnum.NUCLEO_L031K6.build.product_line=STM32L031xx
@@ -358,7 +358,7 @@ Disco.menu.pnum.DISCO_L072CZ_LRWAN1=Discovery L072CZ-LRWAN1
 Disco.menu.pnum.DISCO_L072CZ_LRWAN1.node="DIS_L072Z,NODE_L072CZ"
 Disco.menu.pnum.DISCO_L072CZ_LRWAN1.upload.maximum_size=196608
 Disco.menu.pnum.DISCO_L072CZ_LRWAN1.upload.maximum_data_size=20480
-Disco.menu.pnum.DISCO_L072CZ_LRWAN1.build.mcu=cortex-m0
+Disco.menu.pnum.DISCO_L072CZ_LRWAN1.build.mcu=cortex-m0plus
 Disco.menu.pnum.DISCO_L072CZ_LRWAN1.build.board=DISCO_L072CZ_LRWAN1
 Disco.menu.pnum.DISCO_L072CZ_LRWAN1.build.series=STM32L0xx
 Disco.menu.pnum.DISCO_L072CZ_LRWAN1.build.product_line=STM32L072xx