SWDEV-330455 - Avoid creating different HSA signals for ROCr
SWDEV-330455 - Avoid creating different HSA signals for ROCr

- In ROCr, there is supposed to be exactly one HSA signal ever whose pointer is stored in every hostcall buffer so that device code can find it
- But, hostcallListener->initDevice creates a new HSA signal everytime enableHostcalls() gets called

Change-Id: I100595ec37442bcdb73da5991062f0a474de2935

ROCm-Developer-Tools/ROCclr,ROCm-Developer-Tools/ROCclr