Fix incorrect tilde expansion in environment variable

The previous documentation incorrectly suggested setting the
NOISE_SUPPRESSION_MODEL_NAME variable with a quoted tilde (~).
When quoted, tilde expansion does not occur, leading to an invalid path.

Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>

Author: SurajSonawane2415

tools/plugin/README.md

@@ -121,7 +121,7 @@ repository to make sure OpenVino and OpenCV are configured properly.
 
 4. Set environment variable NOISE_SUPPRESSION_MODEL_NAME to point to the model file
 ```
-export NOISE_SUPPRESSION_MODEL_NAME="~/open_model_zoo/demos/noise_suppression_demo/cpp/intel/noise-suppression-poconetlike-0001/FP16/noise-suppression-poconetlike-0001.xml"
+export NOISE_SUPPRESSION_MODEL_NAME=~/open_model_zoo/demos/noise_suppression_demo/cpp/intel/noise-suppression-poconetlike-0001/FP16/noise-suppression-poconetlike-0001.xml
 
 ```
 5. Enable noise suppression by setting NOISE_SUPPRESSION=true in the tplg-targets for the sof-plugin topology