ACPI: EC: Fix ACPI EC resume non-query interrupt message

When resuming from standby (on a laptop) I see the following message in
my kernel.log:
"ACPI: EC: non-query interrupt received, switching to interrupt mode"
This apparently prevented sony-laptop to properly restore the brightness
level on resume.

The cause: In drivers/acpi/ec.c the acpi_ec_suspend function clears the
GPE mode bit, but this is not restored in acpi_ec_resume (the function
below it). The patch below fixes this by properly restoring the GPE_MODE
bit. Tested and confirmed to work.

Signed-off-by: Almer S. Tigelaar <almer@gnome.org>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Acked-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>