Re-enable acpi by default

Signed-off-by: Graham MacDonald <grahamamacdonald@gmail.com>

sys/src/9/amd64/main.c

@@ -649,6 +649,7 @@ if (1){	acpiinit(); hi("	acpiinit();\n");}
 
 	alloc_cpu_buffers();
 
+	acpistart();
 	print("CPU Freq. %dMHz\n", mach->cpumhz);
 
 	print("schedinit...\n");