MdeModulePkg SataControllerDxe: Use compare logic in if condition

Use compare logic in if condition to fix ECC issue.
It is caused by aa4240edff41034d709938a15b42cf4fd3214386.

Cc: Hao Wu <hao.a.wu@intel.com>
Cc: Dandan Bi <dandan.bi@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Hao Wu <hao.a.wu@intel.com>