Documentation/arch/arm64: Fix typo

Should be 'if' here.

Signed-off-by: Tsung-Han Lin <tsunghan.tw@gmail.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20231203011804.27694-1-tsunghan.tw@gmail.com


Signed-off-by: Will Deacon <will@kernel.org>