AmpereAltraPkg/Ac01PcieLib: drop useless link status register read

Nhi says that reading LINK_CONTROL_LINK_STATUS_REG is redundant; its only
use was debugging (before commit 380b4b40). Thus, we can go farther
than commit 2e27c62e, and remove the MmioRead32() call altogether.

Build-tested with "Jade.dsc".

Cc: Chuong Tran <chuong@os.amperecomputing.com>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Nhi Pham <nhi@os.amperecomputing.com>
Cc: Rebecca Cran <rebecca@os.amperecomputing.com>
Suggested-by: Nhi Pham <nhi@os.amperecomputing.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20231017100507.43573-1-lersek@redhat.com>
Reviewed-by: Rebecca Cran <rebecca@os.amperecomputing.com>
Reviewed-by: Nhi Pham <nhi@os.amperecomputing.com>