platform/x86: dell-laptop: Allocate buffer on heap rather than globally

platform/x86: dell-laptop: Allocate buffer on heap rather than globally

BugLink: http://bugs.launchpad.net/bugs/1755179
commit 9862b43624a5450a097cc4122732857b869dbbca upstream.

There is no longer a need for the buffer to be defined in
first 4GB physical address space.

Furthermore there may be race conditions with multiple different functions
working on a module wide buffer causing incorrect results.

Fixes: 549b4930f057658dc50d8010e66219233119a4d8
Suggested-by: Pali Rohar <pali.rohar@gmail.com>
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>