USB: core/sysfs: fix sparse warnings

Fix 3 sparse warning in drivers/usb/core/sysfs.c.

	warning: symbol '__mptr' shadows an earlier one

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>