MIPS: Fix mdelay(1) for 64bit kernel with HZ == 1000

    
mdelay(1) (i.e. udelay(1000)) does not work correctly due to overflow.
    
1000 * 0x004189374BC6A7f0 = 0x10000000000000180 (>= 2**64)
    
0x004189374BC6A7ef (0x004189374BC6A7f0 - 1) is OK and it is exactly
same as catchall case (0x8000000000000000UL / (500000 / HZ)).
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/delay.h

@@ -52,13 +52,11 @@ static inline void __udelay(unsigned long usecs, unsigned long lpj)
 	unsigned long lo;
 
 	/*
-	 * The common rates of 1000 and 128 are rounded wrongly by the
-	 * catchall case for 64-bit.  Excessive precission?  Probably ...
+	 * The rates of 128 is rounded wrongly by the catchall case
+	 * for 64-bit.  Excessive precission?  Probably ...
 	 */
 #if defined(CONFIG_64BIT) && (HZ == 128)
 	usecs *= 0x0008637bd05af6c7UL;		/* 2**64 / (1000000 / HZ) */
-#elif defined(CONFIG_64BIT) && (HZ == 1000)
-	usecs *= 0x004189374BC6A7f0UL;		/* 2**64 / (1000000 / HZ) */
 #elif defined(CONFIG_64BIT)
 	usecs *= (0x8000000000000000UL / (500000 / HZ));
 #else /* 32-bit junk follows here */