Fix __const_udelay declaration and definition mismatches

The declaration and implementation of __const_udelay use different
names for the parameter on a number of architectures:

include/asm-avr32/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/avr32/lib/delay.c:39:inline void __const_udelay(unsigned long xloops)

include/asm-sh/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/sh/lib/delay.c:22:inline void __const_udelay(unsigned long xloops)

include/asm-m32r/delay.h:15:extern void __const_udelay(unsigned long usecs);
arch/m32r/lib/delay.c:58:void __const_udelay(unsigned long xloops)

include/asm-x86/delay.h:16:extern void __const_udelay(unsigned long usecs);
arch/x86/lib/delay_32.c:82:inline void __const_udelay(unsigned long xloops)
arch/x86/lib/delay_64.c:46:inline void __const_udelay(unsigned long xloops)

The units of the parameter isn't usecs, so that name is definitely
wrong.  It's also not exactly loops, so I suppose xloops is an OK
name.

This patch changes these names from usecs to xloops.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>