x86: Share definition of __is_canonical_address()

[ Upstream commit 1fb85d06 ]

Reduce code duplication by moving canonical address code to a common header
file.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220131072453.2839535-3-adrian.hunter@intel.com


Stable-dep-of: f7993654 ("x86/sev-es: Allow copy_from_kernel_nofault() in earlier boot")
Signed-off-by: Sasha Levin <sashal@kernel.org>