Revert "[chibios] Changed to version 2.6.4"

This reverts commit 4b59fab60d04042ee5ef5c64c2b59062a4e2e82b.

ChibiOS needs first the custom driver for ICU timer (used for PPM at Lisa)
Revert "[chibios] move to official repository"

This reverts commit a191b3b564a37ee02b9463fedd15cee4ed062bce.

Again ChibiOS needs custom driver for ICU_TIMER - TODO push it into mainline