OvmfPkg/LsiScsiDxe: Open PciIo protocol and initialize the device

Open PciIo protocol and use it to initialize the device. The
initialization of LSI 53C895A is simple: just set the SRST bit in
Interrupt Status Zero register to reset the device.

v2:
  - Use the BITx macros for the bit constants
  - Add the closing of PciIo protocol in LsiScsiControllerStop()

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Gary Lin <glin@suse.com>
Message-Id: <20200717061130.8881-8-glin@suse.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

OvmfPkg/LsiScsiDxe/LsiScsi.h

@@ -14,6 +14,9 @@
 
 typedef struct {
   UINT32                          Signature;
+  UINT64                          OrigPciAttrs;
+  EFI_EVENT                       ExitBoot;
+  EFI_PCI_IO_PROTOCOL             *PciIo;
   UINT8                           MaxTarget;
   UINT8                           MaxLun;
   EFI_EXT_SCSI_PASS_THRU_MODE     PassThruMode;