openrisc: delay: fix loops calculation for __const_udelay

The openrisc implementation of __const_udelay casts the result of a
32-bit multiplication to 64 bits and passes the top 32 bits to __delay.
Since there are no casts on the arguments, this results in a __delay of
zero, regardless of the xloops parameter.

This patch fixes the problem by casting xloops to (unsigned long long),
ensuring that the multiplication is not truncated.

Cc: Jon Masters <[e-mail]>
Signed-off-by: Will Deacon <[e-mail]>
Signed-off-by: Jonas Bonn <[e-mail]>

arch/openrisc/lib/delay.c

···
 {
 	unsigned long long loops;
 
-	loops = xloops * loops_per_jiffy * HZ;
+	loops = (unsigned long long)xloops * loops_per_jiffy * HZ;
 
 	__delay(loops >> 32);
 }