opencl : alignment size converted from bits to bytes (ggml-org#7090)

* opencl alignment size should be converted from bits to bytes

Reference: https://registry.khronos.org/OpenCL/specs/3.0-unified/html/OpenCL_API.html#CL_DEVICE_MEM_BASE_ADDR_ALIGN

> Alignment requirement (in bits) for sub-buffer offsets.

* Update ggml-opencl.cpp for readability using division instead of shift

Co-authored-by: Jared Van Bortel <[email protected]>

---------

Co-authored-by: Jared Van Bortel <[email protected]>

Author: albertjin

ggml-opencl.cpp

@@ -2119,6 +2119,7 @@ static size_t ggml_backend_opencl_buffer_type_get_alignment(ggml_backend_buffer_
     if (alignment == (cl_uint)-1) {
         ggml_cl_init();
         clGetDeviceInfo(device, CL_DEVICE_MEM_BASE_ADDR_ALIGN, sizeof(cl_uint), &alignment, NULL);
+        alignment /= 8; // bits to bytes
     }
     return alignment;