W1: ds2490.c correct print message

Corrected print message, it was writing not reading, this also prints the
endpoint used for the write instead of hardcoding it.  Failed to write
1-wire data to ep0x%x: err=%d.

Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>