ARM: hw_breakpoint: make boot quieter without CPUID feature registers

Booting on a v6 core without the CPUID feature registers (e.g. 1136)
leads to a noisy dmesg complaining about their absence.

This patch changes the pr_warning into a pr_warn_once to keep the log
quieter.

Signed-off-by: Will Deacon <[e-mail]>

arch/arm/kernel/hw_breakpoint.c

···
 
 	/* Do we implement the extended CPUID interface? */
 	if (((read_cpuid_id() >> 16) & 0xf) != 0xf) {
-		pr_warning("CPUID feature registers not supported. "
-			   "Assuming v6 debug is present.\n");
+		pr_warn_once("CPUID feature registers not supported. "
+			     "Assuming v6 debug is present.\n");
 		return ARM_DEBUG_ARCH_V6;
 	}