[arm] PR 80389 - if architecture and cpu mismatch, don't print an architecture name...

[arm] PR 80389 - if architecture and cpu mismatch, don't print an architecture name as a CPU name

In this PR we incorrectly print the architecture name in a .cpu
directive in the assembly file when the -mcpu and -march options
conflict (don't target the same base architecture).  In this case the
.arch overrides the .cpu directive and we should emit a .arch option.

PR target/80389
* config/arm/arm.c (arm_configure_build_target): When -mcpu and -arch conflict,
set target->arch_name instead of target->cpu_name.

From-SVN: r246843