tidy up chromeos_setup.sh

tidy up chromeos_setup.sh

- remove unused alex
- streamline Link's config
- remove misleading Daisy config:
  1) armv7=1 does nothing.  We meant to type arm_version=7 here.
  2) arm_neon=1 does nothing unless arm_version == 7.
  3) arm_thumb=0 is the default when arm_version <= 7.
  4) skia_arch_width=32 is the default when skia_arch_type=arm.

I'd just fix this to make Daisy arm_version=7 and arm_neon=1 (and 
arm_thumb=1, which I'm going to separately make the default for 
arm_version=7), but there are known color-order bugs with our
NEON procs that would make Daisy start pushing bad images to
Gold.  Going to take baby steps here...

BUG=skia:1843
Committed: https://skia.googlesource.com/skia/+/3c2809bc612f4a265770914f860d214c9665dc4a

CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Ubuntu-GCC-Arm7-Debug-CrOS_Daisy-Trybot

Committed: https://skia.googlesource.com/skia/+/cb49c07b7361029ba9992ca05f0f2aa5a79a52f5

[mtklein_C, 2015-04-02 14:48:01]

mtklein@chromium.org changed reviewers:
+ borenet@google.com

[borenet, 2015-04-02 15:40:18]

LGTM

[mtklein, 2015-04-02 15:45:19]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-04-02 15:45:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1051253002/1

[commit-bot: I haz the power, 2015-04-02 15:52:47]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/3c2809bc612f4a265770914f860d214c9665dc4a

[mtklein, 2015-04-02 16:01:51]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1059443002/ by mtklein@google.com.

The reason for reverting is: arm_thumb not defined.

[mtklein, 2015-04-02 16:05:23]

The CQ bit was checked by mtklein@google.com

[mtklein, 2015-04-02 16:05:23]

The patchset sent to the CQ was uploaded after l-g-t-m from borenet@google.com
Link to the patchset: https://codereview.chromium.org/1051253002/#ps20001
(title: "restore arm_thumb=0")

[commit-bot: I haz the power, 2015-04-02 16:05:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1051253002/20001

[mtklein, 2015-04-02 16:12:41]

The CQ bit was unchecked by mtklein@google.com

[mtklein, 2015-04-02 16:13:11]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-04-02 16:13:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1051253002/20001

[mtklein, 2015-04-02 16:20:46]

The CQ bit was unchecked by mtklein@google.com

[mtklein, 2015-04-02 16:20:49]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-04-02 16:21:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1051253002/20001

[commit-bot: I haz the power, 2015-04-02 16:28:02]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/cb49c07b7361029ba9992ca05f0f2aa5a79a52f5