Update the hardware support for Dell Precision 5550 in oem-somerville-varys-meta

[Impact]

 * It should have no impact at all because these changes shall have been applied and verified in the corresponding OEM archive before this SRU process.

[Test Plan]

* Install Ubuntu 20.04.x LTS on Dell Precision 5550 and remove oem-somerville-varys-meta manually if any.

 * Enable focal-proposed and execute the update-manager.

 * The update-manager should show "Hardware support for Dell Precision 5550". If not, please change "When there are security updates" and "When there are other updates" in the Updates of software-properties-gtk to "Display immediately", install the older firefox by `sudo apt install firefox=75.0+build3-0ubuntu1` and reboot the system to wait for the update-manager pop up automatically.

 * After it installed oem-somerville-varys-meta by update-manager and reboot the system, you should see the system booting from the linux-oem-20.04c kernel.

[Where problems could occur]

 * oem-somerville-varys-meta is installed but it is not updated to the version in the corresponding OEM archive.

 * The update-manager didn't show "Hardware support for Dell Precision 5550" at all.

[Other Info]

 * You can see all oem-somerville-varys-meta versions on https://people.canonical.com/~oem-enablement/oem-meta-packages/.
 * I have used ppa:oem-solutions-engineers/oem-projects-meta to verify it before this SRU process.