MIPS: Fix potencial build error in <asm/delay.h>

<asm/delay.h> will break if HZ isn't defined.  In 2.6.26 and later we're
usually lucky ...
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/delay.h

@@ -11,6 +11,8 @@
 #ifndef _ASM_DELAY_H
 #define _ASM_DELAY_H
 
+#include <linux/param.h>
+
 extern void __delay(unsigned int loops);
 extern void __ndelay(unsigned int ns);
 extern void __udelay(unsigned int us);