target/arm: Define and use XPSR bit masks

target/arm: Define and use XPSR bit masks

The M profile XPSR is almost the same format as the A profile CPSR,
but not quite. Define some XPSR_* macros and use them where we
definitely dealing with an XPSR rather than reusing the CPSR ones.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 1501692241-23310-9-git-send-email-peter.maydell@linaro.org