drivers/leds/leds-lp5521.c: fix lp5521_read() error handling

Gcc 4.6.2 complains that:

  drivers/leds/leds-lp5521.c: In function `lp5521_load_program':
  drivers/leds/leds-lp5521.c:214:21: warning: `mode' may be used uninitialized in this function [-Wuninitialized]
  drivers/leds/leds-lp5521.c: In function `lp5521_probe':
  drivers/leds/leds-lp5521.c:788:5: warning: `buf' may be used uninitialized in this function [-Wuninitialized]
  drivers/leds/leds-lp5521.c:740:6: warning: `ret' may be used uninitialized in this function [-Wuninitialized]

These are real problems if lp5521_read() returns an error.  When that
happens we should handle it, instead of ignoring it or doing a bitwise
OR with all the other error codes and continuing.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Milo <Milo.Kim@ti.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Bryan Wu <bryan.wu@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>