arm64: cpufeature: Relax checks for AArch32 support at EL[0-2]

arm64: cpufeature: Relax checks for AArch32 support at EL[0-2]

We don't need to be quite as strict about mismatched AArch32 support,
which is good because the friendly hardware folks have been busy
mismatching this to their hearts' content.

  * We don't care about EL2 or EL3 (there are silly comments concerning
    the latter, so remove those)

  * EL1 support is gated by the ARM64_HAS_32BIT_EL1 capability and handled
    gracefully when a mismatch occurs

  * EL0 support is gated by the ARM64_HAS_32BIT_EL0 capability and handled
    gracefully when a mismatch occurs

Relax the AArch32 checks to FTR_NONSTRICT.

Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20200421142922.18950-8-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>