MdePkg:Update Return Error Macro in Base.h

MdePkg:Update Return Error Macro in Base.h

Fixing RETURN_ERROR macro.
It is causing problem in Coverity Static analysis tool as we are directly converting the UINT value to INTN

Changing value from UINT to INTN might cause problem. Here we know that the values would not be in loss of data.
To increase the code quality and increase the static tool analysis score we have to change it

Cc: Jiangang He <jiangang.he@amd.com>
Cc: Neo Hsueh <Hong-Chih.Hsueh@amd.com>
Signed-off-by: Parth Thakkar <ParthRajeshkumar.Thakkar@amd.com>