soc/intel/quark: We're not Broadwell anymore

... even though the author of the code probably wished he was
working on a (much faster) broadwell system instead. Let's fix
the header guard to reflect the right SOC.

Noteworthy: clang detected that this was wrong.

Change-Id: I74c217c0471800f40c31a9ac38ba5396f82cd724
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: https://review.coreboot.org/20387
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/soc/intel/quark/include/soc/cpu.h

@@ -14,7 +14,7 @@
  */
 
 #ifndef _QUARK_CPU_H_
-#define _BROADWELL_CPU_H_
+#define _QUARK_CPU_H_
 
 #include <arch/cpu.h>
 #include <device/device.h>