add an inlined version of iter_div_u64_rem

iter_div_u64_rem is used in the x86-64 vdso, which cannot call other
kernel code.  For this case, provide the always_inlined version,
__iter_div_u64_rem.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/lib/div64.c b/lib/div64.c
index 76c0154..a111eb8 100644
--- a/lib/div64.c
+++ b/lib/div64.c
@@ -105,19 +105,6 @@
  */
 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
 {
-	u32 ret = 0;
-
-	while (dividend >= divisor) {
-		/* The following asm() prevents the compiler from
-		   optimising this loop into a modulo operation.  */
-		asm("" : "+rm"(dividend));
-
-		dividend -= divisor;
-		ret++;
-	}
-
-	*remainder = dividend;
-
-	return ret;
+	return __iter_div_u64_rem(dividend, divisor, remainder);
 }
 EXPORT_SYMBOL(iter_div_u64_rem);