amdgcn: Add gfx1103 target

Add support for the gfx1103 RDNA3 APU integrated graphics devices.  The ROCm
documentation warns that these may not be supported, but it seems to work
at least partially.

gcc/ChangeLog:

	* config.gcc (amdgcn): Add gfx1103 entries.
	* config/gcn/gcn-hsa.h (NO_XNACK): Likewise.
	(gcn_local_sym_hash): Likewise.
	* config/gcn/gcn-opts.h (enum processor_type): Likewise.
	(TARGET_GFX1103): New macro.
	* config/gcn/gcn.cc (gcn_option_override): Handle gfx1103.
	(gcn_omp_device_kind_arch_isa): Likewise.
	(output_file_start): Likewise.
	(gcn_hsa_declare_function_name): Use TARGET_RDNA3, not just gfx1100.
	* config/gcn/gcn.h (TARGET_CPU_CPP_BUILTINS): Add __gfx1103__.
	* config/gcn/gcn.opt: Add gfx1103.
	* config/gcn/mkoffload.cc (EF_AMDGPU_MACH_AMDGCN_GFX1103): New.
	(main): Handle gfx1103.
	* config/gcn/t-omp-device: Add gfx1103 isa.
	* doc/install.texi (amdgcn): Add gfx1103.
	* doc/invoke.texi (-march): Likewise.

libgomp/ChangeLog:

	* plugin/plugin-gcn.c (EF_AMDGPU_MACH): GFX1103.
	(gcn_gfx1103_s): New.
	(isa_hsa_name): Handle gfx1103.
	(isa_code): Likewise.
	(max_isa_vgprs): Likewise.