acer-wmi: Fix capitalisation of GUID in module alias

wmi:6AF4F258-B401-42Fd-BE91-3D4AC2D7C0D3 needs to be
wmi:6AF4F258-B401-42FD-BE91-3D4AC2D7C0D3 in module alias for acer-wmi is
automatically loaded.

Cc: Pali Rohár <pali.rohar@gmail.com>
Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Lee, Chun-Yi <jlee@novell.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>