d/templates: Fixed missed references to gcc-12

Apertis is currently still using gcc-10. A few references to gcc-12 were missed in the last merge, resulting in packages with "gcc-12" in their names being generated and the following error when attempting to install linux-headers-6.1.0-0.deb11.2-amd64:

2023/02/10 03:20:52 apt | The following packages have unmet dependencies:
2023/02/10 03:20:52 apt | linux-headers-6.1.0-0.deb11.2-amd64 : Depends: linux-compiler-gcc-10-x86 but it is not installable
2023/02/10 03:20:52 apt | E: Unable to correct problems, you have held broken packages.

Fix the references so that packages with the correct "gcc-10" naming are generated, resolving the installation issue.

Signed-off-by: Martyn Welch martyn.welch@collabora.com