[arm] Fix gcc.target/arm/pr79058.c

[arm] Fix gcc.target/arm/pr79058.c

This testcase tests 32-bit ARM state functionality, so add the -marm to make it explicit
as well as to avoid Thumb1 hard-float errors for certain toolchain configurations.

     * gcc.target/arm/pr79058.c: Add arm_arm_ok check and -marm to options.

From-SVN: r256878