Work around an ancient GCC bug.

warning: cast from function call of type 'char *' to non-matching type 'long unsigned int'
Remove a redundant cast to ACPI_SIZE for ACPI_OFFSET() macro.

It is already casted to ACPI_SIZE by ACPI_PTR_DIFF() macro.
Merge pull request #42 from juikim/master

Fix couple of trivial problems