drm/amdkfd: Rectify the jiffies calculation error with milliseconds v2

The timeout in milliseconds should not be regarded as jiffies. This
commit fixed that.

v2:
- use msecs_to_jiffies
- change timeout_ms parameter to unsigned int to match msecs_to_jiffies

Signed-off-by: Yong Zhao <yong.zhao@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>