developer_guides: llext_modules.rst: modify broken link for Intel firmware paths

update broken link to Intel firmware paths in llext_modules.rst from
intel_firmware_paths to intel_modular_firmware_paths to point to
correct location and fix doc build errors.

Signed-off-by: Christopher Turner <[email protected]>

Author: cgturner1

developer_guides/firmware/llext_modules.rst

@@ -78,7 +78,7 @@ Installation
 ************
 
 As specified in
-:ref:`Firmware look-up paths per Intel platform <intel_firmware_paths>`
+:ref:`Firmware look-up paths per Intel platform <intel_modular_firmware_paths>`
 the |SOF| Linux kernel driver loads SOF modules by their UUIDs,
 specified in the topology. For SOF in-tree modules the process of creation and
 installation of modules in a deployment tree is automated by the