x86/cpu: Remove "noclflush"

Not really needed anymore and there's clearcpuid=.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220127115626.14179-7-bp@alien8.de

Documentation/admin-guide/kernel-parameters.txt

@@ -3444,8 +3444,6 @@
 
 	nocache		[ARM]
 
-	noclflush	[BUGS=X86] Don't use the CLFLUSH instruction
-
 	delayacct	[KNL] Enable per-task delay accounting
 
 	nodsp		[SH] Disable hardware DSP at boot time.

arch/x86/kernel/cpu/common.c

@@ -1870,14 +1870,6 @@ void identify_secondary_cpu(struct cpuinfo_x86 *c)
 	update_srbds_msr();
 }
 
-static __init int setup_noclflush(char *arg)
-{
-	setup_clear_cpu_cap(X86_FEATURE_CLFLUSH);
-	setup_clear_cpu_cap(X86_FEATURE_CLFLUSHOPT);
-	return 1;
-}
-__setup("noclflush", setup_noclflush);
-
 void print_cpu_info(struct cpuinfo_x86 *c)
 {
 	const char *vendor = NULL;