docs: samples: Update pyocd calls to unified tool subcommands

pyocd 0.14.0 merged its command-line tools into a unified pyocd tool
with subcommands. The separate command-line tools still remain, but are
deprecated. Update all pyocd calls in samples and documentation to use
the new unified pyocd tool with subcommands.

Note that pyocd 0.15.0 has an issue with the command 'pyocd erase',
which was fixed in pyocd 0.16.0.

Signed-off-by: Maureen Helm <maureen.helm@nxp.com>
diff --git a/samples/zephyr/Makefile b/samples/zephyr/Makefile
index 5c3924c..938468e 100644
--- a/samples/zephyr/Makefile
+++ b/samples/zephyr/Makefile
@@ -75,7 +75,7 @@
 
 IMGTOOL = ../../scripts/imgtool.py
 ASSEMBLE = ../../scripts/assemble.py
-PYOCD_FLASHTOOL = pyocd-flashtool
+PYOCD = pyocd
 
 SOURCE_DIRECTORY := $(CURDIR)
 BUILD_DIRECTORY := $(CURDIR)/build/$(BOARD)
@@ -166,16 +166,16 @@
 # are hardcoded at this time.
 
 flash_boot:
-	$(PYOCD_FLASHTOOL) -ce -a 0 mcuboot.bin
+	$(PYOCD) flash -e chip -a 0 mcuboot.bin
 
 flash_hello1:
-	$(PYOCD_FLASHTOOL) -a 0x20000 signed-hello1.bin
+	$(PYOCD) flash -a 0x20000 signed-hello1.bin
 
 flash_hello2:
-	$(PYOCD_FLASHTOOL) -a 0x80000 signed-hello2.bin
+	$(PYOCD) flash -a 0x80000 signed-hello2.bin
 
 flash_full:
-	$(PYOCD_FLASHTOOL) -ce -a 0 full.bin
+	$(PYOCD) flash -e chip -a 0 full.bin
 
 # These test- targets reinvoke make with the configuration set to test
 # various configurations.  This will generally be followed by using