Fixed issue with a BIOS update on Lenovo E485 (v1.54 with AMD 2500U) with
Fedora 30 KDE.

I had an issue on previous BIOS that requires a kernel option to boot on all
kernels (ivrs_ioapic[32]=00:14.0). After BIOS update, this option is not needed
and there is no longer graphic corruption on Kernel 5.2+. This corruption was
impacting at least Firefox, dolphin and the Plasma Desktop.

KDE plasma 5.15.5
mesa 19.1.6
xorg-x11-drv-amdgpu 19.0.1
libdrm 2.4.99

As of my observation, the graphic corruption was introduced in the amdgpu
driver inside Kernel 5.2 and occurs only when forcing boot with the ivrs_ioapic
override.