JOEL4: boot info from the offset of the KIP

The boot info struct was given an absolute address which was given in kernel
space. This should be part of the user space address, in the KIP page.

Signed-off-by: Joel Nider <joel@nider.org>
KOS: missing $ in gdt constant (asm)

Even though the KOS kernel is no longer being developed, it is nonetheless
being used as a reference since it is posted on github and shows up in
searches. In this light I feel it is important to fix any bugs as to not
mislead people accidentally who may rely on this code without realizing its
status.

Constant values in AT&T style assembly should start with a $.
Thanks to Lars Gehlert for pointing out this bug.

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