lpc17_40_userleds.c: Adds the support of Userleds driver which
provides a device to manipulate the 4 leds of the board through the
/dev/userleds.
lpc17_40_leds.c: Removes not used definitions, eg. MBED_LED3_ON.
Board LED Status support(CONFIG_ARCH_LED=y) and Device Drivers/Led
Support(CONFIG_ARCH_USERLED=y) can not be enable together.
Signed-off-by: Gustavo L F Walbon <gwalbon@linux.ibm.com>