[MIPS] Sibyte: Fix ZBbus profiler

 o Fix build error.
 o Handle error returns.
 o Deal with signals received while sleeping.
 o Don't allow to be selected when we're not building the directory with
   the driver anyway.
 o Coding style cleanups.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/sibyte/sb1250/setup.c b/arch/mips/sibyte/sb1250/setup.c
index 1cb042e..87188f0 100644
--- a/arch/mips/sibyte/sb1250/setup.c
+++ b/arch/mips/sibyte/sb1250/setup.c
@@ -16,6 +16,7 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 #include <linux/init.h>
+#include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/reboot.h>
 #include <linux/string.h>
@@ -32,6 +33,7 @@
 unsigned int soc_type;
 unsigned int periph_rev;
 unsigned int zbbus_mhz;
+EXPORT_SYMBOL(zbbus_mhz);
 
 static char *soc_str;
 static char *pass_str;