ACPI / APEI: Make estatus pool allocation a static size

Adding new NMI-like notifications duplicates the calls that grow
and shrink the estatus pool. This is all pretty pointless, as the
size is capped to 64K. Allocate this for each ghes and drop
the code that grows and shrinks the pool.

Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>