mpa: remove bad enum comparison spotted by gcc 4.5.1
tree714a5d831d8d19f92d86029f1acc97cf0a6798a6
drwxr-xr-x - apps
drwxr-xr-x - backdrops
drwxr-xr-x - bootloader
drwxr-xr-x - docs
drwxr-xr-x - firmware
drwxr-xr-x - flash
drwxr-xr-x - fonts
drwxr-xr-x - gdb
drwxr-xr-x - icons
drwxr-xr-x - lib
drwxr-xr-x - manual
drwxr-xr-x - rbutil
drwxr-xr-x - tools
drwxr-xr-x - uisimulator
drwxr-xr-x - utils
drwxr-xr-x - wps