x86/cacheinfo: Fix a -Wtype-limits warning

cpuinfo_x86.x86_model is an unsigned type, so comparing against zero
will generate a compilation warning:

  arch/x86/kernel/cpu/cacheinfo.c: In function 'cacheinfo_amd_init_llc_id':
  arch/x86/kernel/cpu/cacheinfo.c:662:19: warning: comparison is always true \
    due to limited range of data type [-Wtype-limits]

Remove the unnecessary lower bound check.

 [ bp: Massage. ]

Fixes: 68091ee7 ("x86/CPU/AMD: Calculate last level cache ID from number of sharing threads")
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Pu Wen <puwen@hygon.cn>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/1560954773-11967-1-git-send-email-cai@lca.pw

arch/x86/kernel/cpu/cacheinfo.c

@@ -658,8 +658,7 @@ void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id)
 	if (c->x86 < 0x17) {
 		/* LLC is at the node level. */
 		per_cpu(cpu_llc_id, cpu) = node_id;
-	} else if (c->x86 == 0x17 &&
-		   c->x86_model >= 0 && c->x86_model <= 0x1F) {
+	} else if (c->x86 == 0x17 && c->x86_model <= 0x1F) {
 		/*
 		 * LLC is at the core complex level.
 		 * Core complex ID is ApicId[3] for these processors.