Remove unused things from af.h.

[bzbarsky-apple]

Fixes #1939

[github-actions]

PR #25807: Size comparison from 1b2ef05 to 53606da

Decreases (1 build for cc32xx)

platform	target	config	section	1b2ef05	53606da	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL	.debug_abbrev	930286	930266	-20	-0.0
			.debug_aranges	87400	87376	-24	-0.0
			.debug_frame	300336	300288	-48	-0.0
			.debug_info	20239635	20239415	-220	-0.0
			.debug_line	2661958	2661728	-230	-0.0
			.debug_loc	2806731	2806516	-215	-0.0
			.debug_ranges	283424	283400	-24	-0.0
			.debug_str	3027815	3027656	-159	-0.0

Full report (1 build for cc32xx)

platform	target	config	section	1b2ef05	53606da	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL		0	0	0	0.0
			(read only)	645825	645825	0	0.0
			(read/write)	203848	203848	0	0.0
			.ARM.attributes	44	44	0	0.0
			.ARM.exidx	8	8	0	0.0
			.bss	197248	197248	0	0.0
			.comment	194	194	0	0.0
			.data	1480	1480	0	0.0
			.debug_abbrev	930286	930266	-20	-0.0
			.debug_aranges	87400	87376	-24	-0.0
			.debug_frame	300336	300288	-48	-0.0
			.debug_info	20239635	20239415	-220	-0.0
			.debug_line	2661958	2661728	-230	-0.0
			.debug_loc	2806731	2806516	-215	-0.0
			.debug_ranges	283424	283400	-24	-0.0
			.debug_str	3027815	3027656	-159	-0.0
			.ramVecs	780	780	0	0.0
			.resetVecs	64	64	0	0.0
			.rodata	105993	105993	0	0.0
			.shstrtab	232	232	0	0.0
			.stab	204	204	0	0.0
			.stabstr	441	441	0	0.0
			.stack	2048	2048	0	0.0
			.strtab	380469	380469	0	0.0
			.symtab	257408	257408	0	0.0
			.text	537712	537712	0	0.0