[clang][AMDGPU] Remove trialing whitespace in doc

Added by f2a78e6.

Wouldn't normally bother but it's showing up in some CI checks,
just want to reduce the noise.

Author: DavidSpickett

clang/docs/HIPSupport.rst

@@ -176,8 +176,8 @@ Predefined Macros
    * - ``HIP_API_PER_THREAD_DEFAULT_STREAM``
      - Alias to ``__HIP_API_PER_THREAD_DEFAULT_STREAM__``. Deprecated.
 
-Note that some architecture specific AMDGPU macros will have default values when 
-used from the HIP host compilation. Other :doc:`AMDGPU macros <AMDGPUSupport>` 
+Note that some architecture specific AMDGPU macros will have default values when
+used from the HIP host compilation. Other :doc:`AMDGPU macros <AMDGPUSupport>`
 like ``__AMDGCN_WAVEFRONT_SIZE__`` will default to 64 for example.
 
 Compilation Modes