efi: create libacpi

Description:
Refactored ACPICA for partial initialization in the loader.
This work is the final preface for Lua bindings.

Work on this commit involves:
Subset ACPICA for loader land:
For our Lua bindings, we need to be able to walk
the ACPI namespace and evaluate objects.
To do so, we need AcpiInitializeSubsystem, AcpiInitializeTables,
AcpiEnableSubsystem, and AcpiLoadTables.

Notes:
-acpi_detect() moved into libacpi.
-Libacpi conditionally compiles ACPICA and glue code on amd64.
(arm64 will be addressed in a future update)
-AcpiEnableSubsystem is initialized in reduced hardware mode,
but with events enabled. This is so that we do not need to pull
in all of ACPI_HARDWARE, but can evaluate objects.
-Stubbed out Osd functions required for this limited initialization.
-Conditionally exclude functions to make a minimal subset designed
around loader's/lua binding's needs:
--Exclude AcpiInitializeObjects, as we do not need this for walking
the namespace and evaluating objects. (utxfinit.c)
--Exclude notify handlers or fixed event handlers. (evxface.c)
--Stub out print functions, as the loader does not have standard
output. (osunixxf.c)
--Stub out AcpiOsSleep and AcpiOsGetTimer, as the loader is not
multi-threaded and does not implement timers. (osunixxf.c)

Author: kpowkitty

stand/efi/Makefile

@@ -5,6 +5,8 @@ NO_OBJ=t
 SUBDIR.yes+=	libefi
 SUBDIR.${MK_LOADER_IA32}+=	libefi32
 SUBDIR.${MK_FDT}+=	fdt
+SUBDIR.yes+=	libacpi
+SUBDIR.${MK_LOADER_IA32}+=	libacpi32
 SUBDIR.yes+=	.WAIT
 
 SUBDIR.yes+=	boot1 gptboot