target-arm: Fix BASEPRI, BASEPRI_MAX, and FAULTMASK access Correct the decode of the register numbers for BASEPRI, BASEPRI_MAX and FAULTMASK, according to "ARMv7-M Architecture Reference Manual" issue D section "B5.2.3 MRS" and "B5.2.3 MSR". Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>