pseries: Update SLOF firmware image

This is all about TPM fixes and improvements.

The change log is:

Alexey Kardashevskiy (2):
      tcgbios: Fix warnings
      version: update to 20210711

Stefan Berger (9):
      tcgbios: Fix details in log entries
      tcgbios: Fix a typo in the sha256 algo description
      tcgbios: Add implementations for sha1, sha384, and sha512
      tpm: Add firmware API call 2HASH-EXT-LOG
      tcgbios: Change format of S_CRTM_VERSION string to ucs-2
      tcgbios: Use assembly for 32 bit rotr in sha256
      tcgbios: Use The proper sha function for each PCR bank
      tcgbios: Add test cases and test script to run them
      Travis: Add script for running tests on Travis

Thomas Huth (1):
      Fix bad header guard in version.h

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

pc-bios/README

@@ -14,7 +14,7 @@
 - SLOF (Slimline Open Firmware) is a free IEEE 1275 Open Firmware
   implementation for certain IBM POWER hardware.  The sources are at
   https://github.com/aik/SLOF, and the image currently in qemu is
-  built from git tag qemu-slof-20210217.
+  built from git tag qemu-slof-20210711.
 
 - VOF (Virtual Open Firmware) is a minimalistic firmware to work with
   -machine pseries,x-vof=on. When enabled, the firmware acts as a slim shim and