alsa_conformance_test: Fix compile error on linux

Fix error message: "variably modified ‘step_counter’ at file scope"
Fix the package install command as well.

BUG=None
TEST=make alsa_conformance_test

Change-Id: I30603d235912cbbb5460d2444ff60b02586dc804
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/audiotest/+/2057705
Commit-Queue: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Tested-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Reviewed-by: Chih-Yang Hsia <paulhsia@chromium.org>
diff --git a/alsa_conformance_test.md b/alsa_conformance_test.md
index 2780a22..5d7d4e2 100644
--- a/alsa_conformance_test.md
+++ b/alsa_conformance_test.md
@@ -14,14 +14,14 @@
 ```Shell
 sudo apt-get update
 sudo apt-get upgrade
-sudo apt-get install git, pkg-config, build-essential, libasound2-dev
+sudo apt-get install git pkg-config build-essential libasound2-dev
 ```
 
 Make sure these packages are on the device under test(DUT) for testing.
 ```Shell
 sudo apt-get update
 sudo apt-get upgrade
-sudo apt-get install alsa-utils, libasound2-dev
+sudo apt-get install alsa-utils libasound2-dev
 ```
 **NOTE:** ChromeOS has already had these packages.
 
diff --git a/alsa_conformance_test/alsa_conformance_recorder.c b/alsa_conformance_test/alsa_conformance_recorder.c
index b59780d..f3458f9 100644
--- a/alsa_conformance_test/alsa_conformance_recorder.c
+++ b/alsa_conformance_test/alsa_conformance_recorder.c
@@ -11,7 +11,7 @@
 #include "alsa_conformance_recorder.h"
 #include "alsa_conformance_timer.h"
 
-static const int ARRAY_SIZE = 4096;
+#define ARRAY_SIZE 4096
 
 struct alsa_conformance_recorder {
 	unsigned long count;