Input: i8042 - add LoongArch support in i8042-acpipnpio.h

LoongArch uses ACPI and nearly the same as X86/IA64 for 8042. So modify
i8042-acpipnpio.h slightly and enable it for LoongArch in i8042.h. Then
i8042 driver can work well under the ACPI firmware with PNP typed key-
board and mouse configured in DSDT.

Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20220917064020.1639709-2-chenhuacai@loongson.cn
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>