Update README, add SECO intel bblayers

Co-authored-by: Ettore Chimenti <ettore.chimenti@seco.com>
Co-authored-by: Tommaso Merciai <tommaso.merciai@seco.com>
Co-authored-by: Alberto Merciai <alberto.merciai@seco.com>
Signed-off-by: Ettore Chimenti <ettore.chimenti@seco.com>

README.md

@@ -64,6 +64,7 @@ Supported machines:
 - qemux86
 - qemuarm
 - qemuarm64
+- seco-intel-b68 (SECO intel B68)
 
 Example:
 

flavours/linux/bblayers.conf.sample

@@ -10,4 +10,6 @@ BBLAYERS ?= " \
   ##OEROOT##/meta-poky \
   ##OEROOT##/meta-yocto-bsp \
   ##OEROOT##/../meta-ohos/meta-ohos-foundation \
+  ##OEROOT##/../meta-intel \
+  ##OEROOT##/../meta-seco-intel \
   "