musb: enable hostmode on n900 (semi-manual)

musb: enable hostmode on n900 (semi-manual)

With this i'm able to use my LS, FS and HS devices. For this bme should
obviously be stopped.

Do ``cat /proc/driver/musb_hdrc'' to check for DEVCTL state.

Do ``echo hostf > /sys/devices/platform/musb_hdrc/mode'' to switch it to
the host mode in FULL speed; do ``echo hostl >
/sys/devices/platform/musb_hdrc/mode'' to switch it to the host mode in
LOW speed; do ``echo hosth > /sys/devices/platform/musb_hdrc/mode'' for
HIGH speed.

Then apply VBUS and force enumeration.

Proper DEVCTL state in hostmode with the power on VBUS applied (either
internal, or external) is 0x5D for full/high speed, 0x3D for low speed.

Then manually force device enumeration with
``echo F > /proc/driver/musb_hdrc''

``echo peripheral > /sys/devices/platform/musb_hdrc/mode'' to switch it
back (do not forget to start bme afterwards).

You might need to wait for some time before a new attempt to force the
hostmode, calling ``lsusb'' usually helps to bring it back to the
default state.