gpiolib-acpi: Register GpioInt ACPI event handlers from a late_initcall

GpioInt ACPI event handlers may see there IRQ triggered immediately
after requesting the IRQ (esp. level triggered ones). This means that they
may run before any other (builtin) drivers have had a chance to register
their OpRegion handlers, leading to errors like this:

[    1.133274] ACPI Error: No handler for Region [PMOP] ((____ptrval____)) [UserDefinedRegion] (20180531/evregion-132)
[    1.133286] ACPI Error: Region UserDefinedRegion (ID=141) has no handler (20180531/exfldio-265)
[    1.133297] ACPI Error: Method parse/execution failed \_SB.GPO2._L01, AE_NOT_EXIST (20180531/psparse-516)

We already defer the manual initial trigger of edge triggered interrupts
by running it from a late_initcall handler, this commit replaces this with
deferring the entire acpi_gpiochip_request_interrupts() call till then,
fixing the problem of some OpRegions not being registered yet.

Note that this removes the need to have a list of edge triggered handlers
which need to run, since the entire acpi_gpiochip_request_interrupts() call
is now delayed, acpi_gpiochip_request_interrupt() can call these directly
now.

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>