arm64: vdso: use consistent 'abi' nomenclature

arm64: vdso: use consistent 'abi' nomenclature

The current code doesn't use a consistent naming scheme for structures,
enums, or variables, making it harder than necessary to determine the
relationship between these.

Let's make this easier by consistently using 'vdso_abi' nomenclature.
The 'vdso_lookup' array is renamed to 'vdso_info' to describe what it
contains rather than how it is consumed.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200428164921.41641-4-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>