target-arm: Add CP_ACCESS_TRAP_UNCATEGORIZED_EL2, 3

Some coprocessor register access functions need to be able
to report "trap to EL3 with an 'uncategorized' syndrome";
add the necessary CPAccessResult enum and handling for it.

I don't currently know of any registers that need to trap
to EL2 with the 'uncategorized' syndrome, but adding the
_EL2 enum as well is trivial and fills in what would
otherwise be an odd gap in the handling.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1437751263-21913-4-git-send-email-peter.maydell@linaro.org