arm64: fix midr range for Cortex-A57 erratum 832075

Register MIDR_EL1 is masked to get variant and revision fields, then
compared against midr_range_min and midr_range_max when checking
whether CPU is affected by any particular erratum. However, variant
and revision fields in MIDR_EL1 are separated by 16 bits, so the min
and max of midr range should be constructed accordingly, otherwise
the patch will not be applied when variant field is non-0.

Acked-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Bo Yan <byan@nvidia.com>
[will: use MIDR_VARIANT_SHIFT to construct upper bound]
Signed-off-by: Will Deacon <will.deacon@arm.com>

Cc: <stable@vger.kernel.org> # v3.18.y
(cherry picked from commit 6d1966dfd6e0ad2f8aa4b664ae1a62e33abe1998)
Signed-off-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>