s5k3l6xx: Rename test pattern menu

Use "s5k3l6xx" consistently including the "xx" part.
2 jobs for fixes2 in 69 minutes and 44 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #373079
librem5
build:aarch64

00:20:37

passed #373080
librem5:arm64
build:deb

01:09:42