Replace ghes_io{re,un}map_pfn_{nmi,irq}()s use of ioremap_page_range()
with __set_fixmap() as ioremap_page_range() may sleep to allocate a new
level of page-table, even if its passed an existing final-address to
use in the mapping.

The GHES driver can only be enabled for architectures that select
HAVE_ACPI_APEI: Add fixmap entries to both x86 and arm64.

clear_fixmap() does the TLB invalidation in __set_fixmap() for arm64
and __set_pte_vaddr() for x86. In each case its the same as the
respective arch_apei_flush_tlb_one().
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJames Morse <james.morse@arm.com>
Reviewed-by: NBorislav Petkov <bp@suse.de>
Tested-by: NTyler Baicar <tbaicar@codeaurora.org>
Tested-by: NToshi Kani <toshi.kani@hpe.com>
[ For the arm64 bits: ]
Acked-by: NWill Deacon <will.deacon@arm.com>
[ For the x86 bits: ]
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: All applicable <stable@vger.kernel.org>