target/arm: Always use arm_pan_enabled() when checking if PAN is enabled

target/arm: Always use arm_pan_enabled() when checking if PAN is enabled

Currently the code in target/arm/helper.c mostly checks the PAN bits
in env->pstate or env->uncached_cpsr directly when it wants to know
if PAN is enabled, because in most callsites we know whether we are
in AArch64 or AArch32. We do have an arm_pan_enabled() function, but
we only use it in a few places where the code might run in either an
AArch32 or AArch64 context.

For FEAT_NV, when HCR_EL2.{NV,NV1} is {1,1} PAN is always disabled
even when the PSTATE.PAN bit is set, the "is PAN enabled" test
becomes more complicated. Make all places that check for PAN use
arm_pan_enabled(), so we have a place to put the FEAT_NV test.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Miguel Luis <miguel.luis@oracle.com>