This patch zeroes the SCTLR.TRE bit prior to setting the mapping as
cacheable for ARMv7 cores in the decompressor, ensuring that the
memory region attributes are obtained from the C and B bits, not from
the page tables.

Cc: Nicolas Pitre <nico@fluxnic.net>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>