iio: health: afe4404: Fix oob read in afe4404_[read|write]_raw

In the Linux kernel, the following vulnerability has been resolved:

iio: health: afe4404: Fix oob read in afe4404_[read|write]_raw

KASAN report out-of-bounds read as follows:

BUG: KASAN: global-out-of-bounds in afe4404_read_raw+0x2ce/0x380

Read of size 4 at addr ffffffffc00e4658 by task cat/278

Call Trace:

afe4404_read_raw

iio_read_channel_info

dev_attr_show

The buggy address belongs to the variable:

afe4404_channel_leds+0x18/0xffffffffffffe9c0

This issue can be reproduce by singe command:

$ cat /sys/bus/i2c/devices/0-0058/iio\:device0/in_intensity6_raw

The array size of afe4404_channel_leds and afe4404_channel_offdacs

are less than channels, so access with chan->address cause OOB read

in afe4404_[read|write]_raw. Fix it by moving access before use them.