OvmfPkg/LsiScsiDxe: Report Targets and LUNs

Implement LsiScsiGetNextTargetLun(), LsiScsiBuildDevicePath(),
LsiScsiGetTargetLun(), and LsiScsiGetNextTarget() to report Targets and
LUNs and build the device path.

This commit also introduces two PCD value: PcdLsiScsiMaxTargetLimit and
PcdLsiScsiMaxLunLimit as the limits for Targets and LUNs.

v3:
  - Update the range of LUN in the assertioin
  - Squash the spurious newline into the previous commit
v2:
  - Zero out (*Target) in LsiScsiGetTargetLun()
  - Use CopyMem() instead of the one-byte shortcut to copy target from
    ScsiDevicePath->Pun
  - Add asserts for PcdLsiScsiMaxTargetLimit and PcdLsiScsiMaxLunLimit

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: <20200717061130.8881-7-glin@suse.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

OvmfPkg/LsiScsiDxe/LsiScsiDxe.inf

@@ -27,7 +27,9 @@
 [LibraryClasses]
   BaseLib
   BaseMemoryLib
+  DebugLib
   MemoryAllocationLib
+  PcdLib
   UefiBootServicesTableLib
   UefiDriverEntryPoint
   UefiLib
@@ -35,3 +37,7 @@
 [Protocols]
   gEfiExtScsiPassThruProtocolGuid        ## BY_START
   gEfiPciIoProtocolGuid                  ## TO_START
+
+[FixedPcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdLsiScsiMaxTargetLimit   ## CONSUMES
+  gUefiOvmfPkgTokenSpaceGuid.PcdLsiScsiMaxLunLimit      ## CONSUMES