dev: fix device number check error in IDE controller

Fixed a typo between 3 and 4.

Change-Id: I1470e30c4d472587db0b9da5512b24ab92f1fd65
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/64052
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
1 file changed