[media] smiapp: Fix determining the need for 8-bit read access

8-bit reads are needed in some cases; however the condition used was wrong.
Regular access (register width) was used if:

	len == SMIAPP_REG_8BIT && !only8

This causes 8-bit read access to be used always. The operator should be ||
instead: regular access can be used for 8-bit reads OR if allowed otherwise.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>