aarch64: Add support for Cortex-X1C CPU.

This patch adds support for Cortex-X1C CPU.

Regards,
Srinath.

gcc/ChangeLog:

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

	* config/aarch64/aarch64-cores.def (AARCH64_CORE): Add Cortex-X1C
	CPU.
	* config/aarch64/aarch64-tune.md: Regenerate.
	* doc/gcc/gcc-command-options/machine-dependent-options/aarch64-options.rst:
	Document Cortex-X1C CPU.