Remove HIP_NUM_KERNELS_INFLIGHT. (redundant with HCC controls)

docs/markdown/hip_porting_guide.md

@@ -569,7 +569,6 @@ HIP_TRACE_API                  =  0 : Trace each HIP API call.  Print function n
 HIP_TRACE_API_COLOR            = green : Color to use for HIP_API.  None/Red/Green/Yellow/Blue/Magenta/Cyan/White
 HIP_PROFILE_API                 =  0 : Add HIP function begin/end to ATP file generated with CodeXL
 HIP_VISIBLE_DEVICES            =  0 : Only devices whose index is present in the secquence are visible to HIP applications and they are enumerated in the order of secquence
-HIP_NUM_KERNELS_INFLIGHT       = 128 : Number of kernels per stream
 
 ```