ArmPlatformPkg/PrePeiCore: Invoke constructors for SEC phase

ArmPlatformPkg/PrePeiCore: Invoke constructors for SEC phase

On platforms that do not have the serial console port pre-initialized
prior to the SEC phase and due to the absence of a call to
"SerialPortInitialize", this results in missing debug logs. So, call
the auto-generated "ProcessLibraryConstructorList" function from SEC
phase to have all the dependent library constructors called
(this includes a call to "SerialPortInitialize").

Signed-off-by: Rohit Mathew <rohit.mathew@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>