cli: Add new write-protect CLI

Add a new write-protect CLI that is based on the classic-CLI feature
in flashrom/master. The syntax is slighty different: With the new
CLI wrapper, we can either call it as `flashprog write-protect` or
`flashprog wp`. To keep the CLI code clean, we allow only one write-
protection operation per call.

For instance, the write-protection status can then be queried like
this:

  $ flashprog wp status -p ch341a_spi

Change-Id: I32818b58c9db939719913fc63063c41a27876554
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/72991
diff --git a/Makefile b/Makefile
index 65b808b..cc6e4d4 100644
--- a/Makefile
+++ b/Makefile
@@ -401,7 +401,7 @@
 ###############################################################################
 # Frontend related stuff.
 
-CLI_OBJS = cli.o cli_config.o cli_classic.o cli_output.o cli_common.o print.o
+CLI_OBJS = cli.o cli_config.o cli_wp.o cli_classic.o cli_output.o cli_common.o print.o
 
 # By default version information will be fetched from Git if available.
 # Otherwise, versioninfo.inc stores the metadata required to build a
@@ -925,7 +925,7 @@
 endif
 
 OBJS = $(CHIP_OBJS) $(PROGRAMMER_OBJS) $(LIB_OBJS)
-MANS = $(PROGRAM).8 $(PROGRAM)-config.8
+MANS = $(PROGRAM).8 $(PROGRAM)-config.8 $(PROGRAM)-write-protect.8
 
 all: $(PROGRAM)$(EXEC_SUFFIX) $(MANS)
 ifeq ($(ARCH), x86)