updated wording around supported linux environments (#642)

* updated wording around supported linux environments

* Update docs/install/rocDecode-prerequisites.rst

Co-authored-by: Leo Paoletti <164940351+lpaoletti@users.noreply.github.com>

* Update docs/install/rocDecode-prerequisites.rst

Co-authored-by: Leo Paoletti <164940351+lpaoletti@users.noreply.github.com>

* SLES 15-SP5 isn't supported; removed

* updated SLES to SP6/7

---------

Co-authored-by: Rajy Rawther <Rajy.MeeyakhanRawther@amd.com>
Co-authored-by: Leo Paoletti <164940351+lpaoletti@users.noreply.github.com>

[ROCm/rocdecode commit: 2e38f502ab]

projects/rocdecode/README.md

@@ -233,7 +233,7 @@ You can find rocDecode Docker containers in our
 * Linux
   * Ubuntu - `22.04` / `24.04`
   * RHEL - `8` / `9`
-  * SLES - `15 SP5`
+  * SLES - `15 SP6` / `15 SP7`
 * ROCm: `7.0.0`
 * libva-amdgpu-dev - `2.16.0`
 * mesa-amdgpu-va-drivers - `1:24.3.0`