checkpatch.conf: Update rules

- Remove the "MISSING_SPACE" check which checks for breaks at a space in
a string concatenation.  Most of the time this makes sense, but we
occasionally need to break where there isn't a space, so having a hard
rule doesn't always work.

- Don't check the vendorcode directory for compliance to coreboot's
code format rules.

Change-Id: Ic07677b19520b5d22363834c77f5dee7bba9e429
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/18569
Tested-by: build bot (Jenkins)
Reviewed-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>

.checkpatch.conf

@@ -15,6 +15,7 @@
 --ignore AVOID_EXTERNS
 --ignore VOLATILE
 --ignore CONFIG_DESCRIPTION
+--ignore MISSING_SPACE
 
 # FILE_PATH_CHANGES seems to not be working correctly. It will
 # choke on added / deleted files even if the MAINTAINERS file
@@ -24,3 +25,7 @@
 # This one has a linux path hard coded, so it would choke on
 # some commits unnecessarily.
 --ignore EXECUTE_PERMISSIONS
+
+# Exclude the vendorcode directory
+--exclude src/vendorcode
+