Classify methods in FAFTClient

There are too many methods in FAFTClient, so this CL is to classify them into
several groups: ec, bios, kernel. Methods which can be put into one of the
target group should be renamed with format _[group name]_[method name].
For example, dump_firmware should be modified to bios_dump. To call methods in
FAFTClient, use [group name].[method name].

BUG=chromium-os:36429
TEST=run firmware update tests

Change-Id: I7ead01246121b454c0a9f29e10bd026a77925e4f
Reviewed-on: https://gerrit.chromium.org/gerrit/38186
Reviewed-by: Tom Wai-Hong Tam <[email protected]>
Commit-Ready: Chun-Ting Chang <[email protected]>
Tested-by: Chun-Ting Chang <[email protected]>
diff --git a/server/site_tests/firmware_DevScreenTimeout/firmware_DevScreenTimeout.py b/server/site_tests/firmware_DevScreenTimeout/firmware_DevScreenTimeout.py
index 2a3dd28..0005d92 100644
--- a/server/site_tests/firmware_DevScreenTimeout/firmware_DevScreenTimeout.py
+++ b/server/site_tests/firmware_DevScreenTimeout/firmware_DevScreenTimeout.py
@@ -52,7 +52,7 @@
         Raises:
           error.TestError: If the firmware-boot-time file does not exist.
         """
-        [fw_time] = self.faft_client.run_shell_command_get_output(
+        [fw_time] = self.faft_client.system.run_shell_command_get_output(
                 'cat /tmp/firmware-boot-time')
         logging.info('Got firmware boot time: %s', fw_time)
         if fw_time: