[MIPS] Fixup migration to GENERIC_TIME

Since we already moved to GENERIC_TIME, we should implement alternatives
of old do_gettimeoffset routines to get sub-jiffies resolution from
gettimeofday().  This patch includes:

 * MIPS clocksource support (based on works by Manish Lachwani).
 * remove unused gettimeoffset routines and related codes.
 * remove unised 64bit do_div64_32().
 * simplify mips_hpt_init. (no argument needed, __init tag)
 * simplify c0_hpt_timer_init. (no need to write to c0_count)
 * remove some hpt_init routines.
 * mips_hpt_mask variable to specify bitmask of hpt value.
 * convert jmr3927_do_gettimeoffset to jmr3927_hpt_read.
 * convert ip27_do_gettimeoffset to ip27_hpt_read.
 * convert bcm1480_do_gettimeoffset to bcm1480_hpt_read.
 * simplify sb1250 hpt functions. (no need to subtract and shift)
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c
index 4cf0c06..69e424e 100644
--- a/arch/mips/dec/time.c
+++ b/arch/mips/dec/time.c
@@ -160,11 +160,6 @@
 	return ioasic_read(IO_REG_FCTR);
 }
 
-static void dec_ioasic_hpt_init(unsigned int count)
-{
-	ioasic_write(IO_REG_FCTR, ioasic_read(IO_REG_FCTR) - count);
-}
-
 
 void __init dec_time_init(void)
 {
@@ -174,11 +169,9 @@
 	mips_timer_state = dec_timer_state;
 	mips_timer_ack = dec_timer_ack;
 
-	if (!cpu_has_counter && IOASIC) {
+	if (!cpu_has_counter && IOASIC)
 		/* For pre-R4k systems we use the I/O ASIC's counter.  */
 		mips_hpt_read = dec_ioasic_hpt_read;
-		mips_hpt_init = dec_ioasic_hpt_init;
-	}
 
 	/* Set up the rate of periodic DS1287 interrupts.  */
 	CMOS_WRITE(RTC_REF_CLCK_32KHZ | (16 - __ffs(HZ)), RTC_REG_A);