Move the checks out of the parsing loop and into the
restore function.  This more closely mirrors the code
structure in the kernel, and is slightly clearer.

Reject rather than silently skip incorrect VL and SVE record sizes,
bringing our checks in to line with those the kernel does.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220708151540.18136-40-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>