ACPI: fix a section mismatch

WARNING: drivers/acpi/acpi.o(.text+0xeda): Section mismatch in reference from the function acpi_os_initialize1() to the function .init.text:set_osi_linux()

The function acpi_os_initialize1() references
the function __init set_osi_linux().

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>