Call cpu_setup() immediately after the page tables are installed. This

enables data cache and other chip-specific features.  It was previously
done via an early SYSINIT, but it was being done after pmap and vm setup,
and those setups need to use mutexes.  On some modern ARM platforms,
the ldrex/strex instructions that implement mutexes require the data cache
to be enabled.

A nice side effect of enabling caching earlier is that it eliminates the
multi-second pause that used to happen early in boot while physical memory
and pmap and vm were being set up.  On boards with 1 GB or more of ram
this pause was very noticible, sometimes 5-6 seconds.

PR:		arm/183740

sys/arm/arm/machdep.c

@@ -361,7 +361,6 @@ cpu_startup(void *dummy)
 #endif
 #endif
 
-	cpu_setup("");
 	identify_arm_cpu();
 
 	printf("real memory  = %ju (%ju MB)\n", (uintmax_t)ptoa(physmem),
@@ -1430,6 +1429,12 @@ initarm(struct arm_boot_params *abp)
 	cpu_tlb_flushID();
 	cpu_domains(DOMAIN_CLIENT << (PMAP_DOMAIN_KERNEL * 2));
 
+	/*
+	 * Now that proper page tables are installed, call cpu_setup() to enable
+	 * instruction and data caches and other chip-specific features.
+	 */
+	cpu_setup("");
+
 	/*
 	 * Only after the SOC registers block is mapped we can perform device
 	 * tree fixups, as they may attempt to read parameters from hardware.