pseries: Update SLOF firmware image

pseries: Update SLOF firmware image

This is mostly compiler warnings fixed but while doing this,
a bug in MIN() in tcgbios was found.

Alexey Kardashevskiy (14):
      helpers: Define MIN()
      libc: Compile with -Wextra
      elf: Compile with -Wextra
      usb: Compile with -Wextra
      veth: Compile with -Wextra
      virtio: Compile with -Wextra
      e1000: Compile with -Wextra
      libnet: Compile with -Wextra
      libhv: Compile with -Wextra
      libnvram: Compile with -Wextra
      libtpm: Compile with -Wextra
      slof/prim: Compile with -Wextra
      Makefile: Actually compile with -Wextra
      version: update to 20210217

Thomas Huth (1):
      virtio-serial: Remove superfluous serial-* words

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