JOEL4: added clobber lists in GDT_Load

Two registers were being used in inline assembly functions but the compiler
wasn't being notified. That lead to a problem with a local variable becoming
inaccessible when the code was built with optimizations on.

Signed-off-by: Joel Nider <joel@nider.org>
JOEL4: boot module info in KIP was incorrect

Fixed up some bugs related to the location of the boot module info. There was
some confusion regarding which pointers should be relative to the KIP, and
which should be absolute. I also added some alignment, but there is more work
to be done here yet.

Signed-off-by: Joel Nider <joel@nider.org>