[media] s5p-jpeg: exynos3250: fix erroneous reset procedure

The first while loop in the function exynos3250_jpeg_reset had no chance
to be executed because the reg variable was initialized to 0.
Initialize reg variable to 1 to fix the issue.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Reported-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>