README: document spi flash controller

README.md

diff --git a/README.md b/README.md
index 8273a88..e162c59 100644
--- a/README.md
+++ b/README.md
@@ -6,10 +6,11 @@
 
  1. A 3-stage, in-order 32-bit Lanai core
  2. 2KB of SRAM
- 3. A Wishbone interconnect/fabric
- 4. An SPI controller
- 5. A GPIO controller
- 6. A simple timer
+ 3. An SPI flash memory controller with 1024kb of instruction/data cache
+ 3. A Wishbone interconnect/fabric containing:
+   1. An SPI controller
+   2. A GPIO controller
+   3. A simple timer
 
 Notably absent are: an interrupt system and a debug interface.