drm/amdkfd: fix the warning for potential insecure string

drm/amdkfd: fix the warning for potential insecure string

Below is the warning thrown by the clang compiler:
linux/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:588:9: warning: format string is not a string literal (potentially insecure) [-Wformat-security]
                                           stats_dir_filename);
                                           ^~~~~~~~~~~~~~~~~~
linux/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:588:9: note: treat the string as an argument to avoid this
                                           stats_dir_filename);
                                           ^
                                           "%s",
linux/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:635:18: warning: format string is not a string literal (potentially insecure) [-Wformat-security]
                                           p->kobj, counters_dir_filename);
                                                    ^~~~~~~~~~~~~~~~~~~~~
linux/drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:635:18: note: treat the string as an argument to avoid this
                                           p->kobj, counters_dir_filename);
                                                    ^
                                                    "%s",

Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
CC: Philip Yang <philip.yang@amd.com>
CC: Felix Kuehling <felix.kuehling@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>