miscellaneous code improvements for sony-laptop

Hello,

here is the first part of the V2 patches sent by me on the 3rd of June. As I have no spare time for coding at the moment, I have to split the previous patchset into two parts, I need more time for some patches while I have the first ones ready laying around. So these patches I'm sending include improvements to the current code and minor support extension, but no new features, that will come later in the second part. Note that patch numbers no longer match with the previous patchset that should be discarded, as is being totally replaced by this set and by the next one, available hopefully soon.

These patches are also available at
http://www.absence.it/vaio-acpi/source/patches/patchset-v2/