Make timestamp collection conditional in hardwaremain.c

Otherwise it breaks 486 boards without RDTSC, ending with
exception 6.

It ends like this on bifferboard:

Jumping to image.
Unexpected Exception: 6 @ 10:001007e3 - Halting
Code: 0 eflags: 00000016
eax: 001001fe ebx: 00100118 ecx: 00000000 edx: 00108e00
edi: 0010aaf8 esi: 00000000 ebp: 00117ff4 esp: 00117fd8

Please keep in mind 486, dont use rdtsc/cpuid in generic code, or if you do make sure make it non-default option.

Change that broke it: http://review.coreboot.org/#/c/749/7/src/boot/hardwaremain.c

Change-Id: I974b25377c20a11430b35b24dcc275d8cbfd2b9a
Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Reviewed-on: http://review.coreboot.org/925
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
diff --git a/src/boot/hardwaremain.c b/src/boot/hardwaremain.c
index 489caa3..532135f 100644
--- a/src/boot/hardwaremain.c
+++ b/src/boot/hardwaremain.c
@@ -57,9 +57,10 @@
 void hardwaremain(int boot_complete)
 {
 	struct lb_memory *lb_mem;
+#if CONFIG_COLLECT_TIMESTAMPS
 	tsc_t timestamps[6];
-
 	timestamps[0] = rdtsc();
+#endif
 	post_code(POST_ENTRY_RAMSTAGE);
 
 	/* console_init() MUST PRECEDE ALL printk()! */
@@ -81,26 +82,37 @@
 	/* FIXME: Is there a better way to handle this? */
 	init_timer();
 
+#if CONFIG_COLLECT_TIMESTAMPS
 	timestamps[1] = rdtsc();
+#endif
 	/* Find the devices we don't have hard coded knowledge about. */
 	dev_enumerate();
 	post_code(POST_DEVICE_ENUMERATION_COMPLETE);
 
+#if CONFIG_COLLECT_TIMESTAMPS
 	timestamps[2] = rdtsc();
+#endif
 	/* Now compute and assign the bus resources. */
 	dev_configure();
 	post_code(POST_DEVICE_CONFIGURATION_COMPLETE);
 
+#if CONFIG_COLLECT_TIMESTAMPS
 	timestamps[3] = rdtsc();
+#endif
 	/* Now actually enable devices on the bus */
 	dev_enable();
 
+#if CONFIG_COLLECT_TIMESTAMPS
 	timestamps[4] = rdtsc();
+#endif
 	/* And of course initialize devices on the bus */
 	dev_initialize();
 	post_code(POST_DEVICES_ENABLED);
 
+#if CONFIG_COLLECT_TIMESTAMPS
 	timestamps[5] = rdtsc();
+#endif
+
 #if CONFIG_WRITE_HIGH_TABLES == 1
 	cbmem_initialize();
 #if CONFIG_CONSOLE_CBMEM