drm/amd/display: Fix misuse of /** to /* in 'dce_i2c_hw.c'

Fix the comment style before cntl_stuck_hw_workaround() by replacing
'/**' with '/*' since it is not a kdoc comment.

Fixes the below with gcc W=1:
display/dc/dce/dce_i2c_hw.c:380: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* If we boot without an HDMI display, the I2C engine does not get
  initialized

Fixes: 04d57f44 ("drm/amd/display: Workaround for stuck I2C arbitrage")
Cc: Alvin Lee <alvin.lee2@amd.com>
Cc: Dominik Kaszewski <dominik.kaszewski@amd.com>
Cc: Ivan Lipski <ivan.lipski@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Tom Chung <chiahsuan.chung@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>