arm: Add support for Cortex-X1C CPU.

arm: Add support for Cortex-X1C CPU.

This patch adds support for Cortex-X1C CPU in Arm.

bfd/ChangeLog:

2022-11-09  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * cpu-arm.c (processors): Add Cortex-X1C CPU entry.

gas/ChangeLog:

2022-11-09  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * NEWS: Update docs.
        * config/tc-arm.c (arm_cpus): Add cortex-x1c to -mcpu.
        * doc/c-arm.texi: Update docs.
        * testsuite/gas/arm/cpu-cortex-x1c.d: New test.