add MSC (Mass Storage Class) support
Allow more than one usbd_register_set_config_callback

In a composite device if one want to separate code
for each interface, usbd_register_set_config_callback
can now register more than one callback.

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
USB: Fix definition of function according to previous commit.
[l1-flash/eeprom] Add lock/unlock/eeprom helper routines
stm32: timers: Fix edge polarity setup

The CCxP/CCxNP bits are actually separated by a reserved bit, so the
correct mask is 0xa, (0b1010) not 0x6 (0b0110)

Reported by PyroDevil on the mailinglist
stm32: timers: fix mixup between TIMx_CCMR1 and TIMx_CCMR2 in timer_set_oc_mode()
stm32f3: drop redundant gpio.c

All methods in this file are in either
* common/gpio_common_all.c
* common/gpio_common_f0234.c

Those other files have better doxygen commentary, this file should never
have been added.
tiva lm4f: ssi: Initial implementation for SSI peripheral
docs: fix link from stm32f3 to stm32f0

Incorrectly pointed to f1.
Makefile: fix build for directories with spaces

When full path of a source directory has spaces in it, that makes
shell and Make split the path, so special treatment is
necessary. Additionally, @F doesn't honour the escaping, so has to be
avoided.

Reported-by: Roman Faizullin <roman@faizullin.info>
Signed-off-by: Paul Fertser <fercerpav@gmail.com>