eeepc-laptop: pull out ACPI_STORE_FUNC and ACPI_SHOW_FUNC macros

Pull out macros EEEPC_ACPI_STORE_FUNC and EEEPC_ACPI_SHOW_FUNC. These
macros define functions that call store_sys_acpi() and show_sys_acpi()
respectively. This helps prevent duplication later on.

Signed-off-by: Frans Klaver <fransklaver@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>