[doc] keys.conf.example: Add 5 missing keys.

Missing keys:
* wup-starbuck-wiiu-common
* cat-starbuck-wiiu-common
* ctr-spi-boot
* ctr-dev-spi-boot
* ctr-dev-FixedCryptoKey

Fixes #429: 5 keys missing from keys.conf.example
Reported by @RuiNtD.

doc/keys.conf.example

@@ -30,13 +30,21 @@ rvl-sd-aes=
 rvl-sd-iv=
 rvl-sd-md5=
 
+######## Nintendo Wii U ########
+
+# Wii U common key
+wup-starbuck-wiiu-common=
+
+# Wii U debug common key
+cat-starbuck-wiiu-common=
+
 ######## Nintendo 3DS ########
 
 ### NOTE: For keys that don't depend on title contents,
 ### if KeyNormal is present, it will be used. Otherwise,
 ### KeyX, KeyY, and the scrambling constant will be used.
 
-### Key scrambler constants.
+### Key scrambler constants
 ### "<<<" == rotate left
 
 # TWL key scrambler: KeyNormal = ((KeyX ^ KeyY) + constant) <<< 42
@@ -108,6 +116,13 @@ ctr-dev-Slot0x3DKeyNormal-3=
 ctr-dev-Slot0x3DKeyNormal-4=
 ctr-dev-Slot0x3DKeyNormal-5=
 
+# Fixed Crypto Key, used by certain titles on devkits (title_id.hi & 0x10)
+ctr-dev-FixedCryptoKey=
+
+# SPI boot keys, used for ntrboothax in some cases
+ctr-spi-boot=
+ctr-dev-spi-boot=
+
 ######## Microsoft Xbox 360 ########
 
 xbox360-xex1=