COMPMID-3926: Floor CTS failing in Neon

Depending n the value of `len`, the left-over loop might end up
writing/reading out-of-bounds, therefore corrupting the memory.

Change-Id: I1b0bb300f3e5ea668b585266e1aa6af7f93a5d1e
Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4290
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Manuel Bottini <manuel.bottini@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/NEON/kernels/floor/impl/fp16_neon_floor.cpp b/src/core/NEON/kernels/floor/impl/fp16_neon_floor.cpp
index 3222fa9..f0d9efb 100644
--- a/src/core/NEON/kernels/floor/impl/fp16_neon_floor.cpp
+++ b/src/core/NEON/kernels/floor/impl/fp16_neon_floor.cpp
@@ -53,7 +53,7 @@
         pdst += step;
     }
 
-    for(; len >= 0; --len)
+    for(; len > 0; --len)
     {
         *pdst++ = std::floor(*psrc++);
     }