s390/delay: sync comment within __delay() with reality

The comment within __delay() is outdated and does not reflect anymore
what the function is doing. Therefore replace the comment.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/lib/delay.c

@@ -14,11 +14,8 @@
 void __delay(unsigned long loops)
 {
 	/*
-         * To end the bloody studid and useless discussion about the
-         * BogoMips number I took the liberty to define the __delay
-         * function in a way that that resulting BogoMips number will
-         * yield the megahertz number of the cpu. The important function
-         * is udelay and that is done using the tod clock. -- martin.
+	 * Loop 'loops' times. Callers must not assume a specific
+	 * amount of time passes before this function returns.
 	 */
 	asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
 }