[media] ov7670: check read error also for REG_AECHH on ov7670_s_exp()

ov7670_s_exp() checks read error for 2 registers: REG_COM1
and REG_COM8. But, although it uses the value latter, it
doesn't check errors on REG_AECHH read. Yet, as it is doing
a bitmask operation there, the read operation should succeed.

So, fix the code to also check if this succeeded.

This fixes this smatch report:
	drivers/media/i2c/ov7670.c:1366 ov7670_s_exp() warn: inconsistent indenting

Compile-tested only.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>