spec: add flash layout for Bletchley and Greatlakes

Summary:
We didn't specify the requirements on the flash layout
for Bletchley and Greatlakes.  Add it now.

Test Plan: Doc only.

Reviewed By: garnermic

fbshipit-source-id: 3b8254cf2ac475b7f5b07c965fda278787b4c94e

Author: williamspatrick

meta-facebook/spec/bletchley/FEATURES.md

@@ -16,6 +16,8 @@
     - Port platform specific u-boot changes.
 - [X] P0 **Kernel Porting**
     - Port platform specific Kernel changes.
+- [ ] P1 **Flash Layout**
+    - Implement the required flash layout.
 - [X] P0 **I2C device tree**
     - Create device tree entries for i2c devices (and enable associated
       drivers).

meta-facebook/spec/common/lf-openbmc/features/infrastructure/file-system-layout.md

@@ -0,0 +1,18 @@
+The flash should layout shall contain the following in a static layout on
+redundant flash devices (unless specified otherwise):
+
+- u-boot SPL
+- u-boot environment
+- image metadata
+- u-boot
+- kernel and initramfs FIT image
+- persistent data store
+
+The persistent data store should only be present on the non-Recovery flash
+device.  The persistent data store should not be mounted if the BMC has booted
+into the Recovery image.
+
+The initramfs must contain the full rootfs image so that the BMC image can be
+updated while running.
+
+

meta-facebook/spec/greatlakes/FEATURES.md

@@ -32,6 +32,8 @@
     - Port platform specific u-boot changes
 - [ ] P0 **Kernel Porting**
     - Port platform specific Kernel changes
+- [ ] P1 **Flash Layout**
+    - Implement the required flash layout.
 - [ ] P0 **I2C device tree**
     - Create device tree entries for i2c devices (and enable associated
       drivers)
@@ -80,7 +82,7 @@
       after reboot or power-cycle), a method is needed to query current
       running firmware and firmware to be activated
 - [ ] P2 **FW WDT Auto-recovery**
-    - If a WDT triggers while loading a new firmware image, the BMC shall 
+    - If a WDT triggers while loading a new firmware image, the BMC shall
       recover to a known good version of firmware for the affected device
       (e.g. BIC, BIOS, CPLD or BMC)
 - [ ] P0 **ASD Jumper Detection**