util/lint: Run lint-extended-007-checkpatch checks in parallel

Instead of checking each directory in series, kick off all the checks
in parallel and then wait for them to finish.  Failures print out with
file information, so mixing output isn't a problem.  This reduces
the time it takes to run on lumberingbuilder from 31 seconds to 6.

Change-Id: I1252a68a723370389d399f3d1a2aff3fad64c365
Signed-off-by: Martin Roth <gaumless@gmail.com>
Reviewed-on: https://review.coreboot.org/26995
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

util/lint/lint-extended-007-checkpatch

@@ -15,30 +15,24 @@
 #
 # DESCR: Run checkpatch on directories that are known good
 
-# Top level
-util/lint/lint-007-checkpatch "src/acpi"
+PIDS=""
+DIRS="src/acpi \
+src/cpu/armltd src/cpu/qemu-power8 src/cpu/qemu-x86 \
+src/drivers/dec src/drivers/gic src/drivers/ti \
+src/ec/purism \
+src/include/boot src/include/superio src/include/sys \
+src/mainboard/adlink src/mainboard/linutop \
+src/mainboard/purism src/mainboard/ti \
+src/soc/rdc \
+src/superio/acpi src/superio/common \
+"
 
-#src/cpu
-util/lint/lint-007-checkpatch "src/cpu/armltd src/cpu/qemu-power8 \
-src/cpu/qemu-x86"
+for directory in $DIRS; do
+	util/lint/lint-007-checkpatch "$directory" &
+	PIDS="$PIDS $!"
+done
 
-#src/drivers
-util/lint/lint-007-checkpatch "src/drivers/dec  src/drivers/gic \
-src/drivers/ti"
-
-#src/ec
-util/lint/lint-007-checkpatch "src/ec/purism"
-
-#src/include
-util/lint/lint-007-checkpatch "src/include/boot src/include/superio \
-src/include/sys"
-
-#src/mainboard
-util/lint/lint-007-checkpatch "src/mainboard/adlink src/mainboard/linutop \
-src/mainboard/purism src/mainboard/ti"
-
-# src/soc
-util/lint/lint-007-checkpatch "src/soc/rdc"
-
-# src/superio
-util/lint/lint-007-checkpatch "src/superio/acpi src/superio/common"
+# wait for tests to finish.
+for pid in $PIDS; do
+	wait "$pid"
+done