Staging: bcm: Move directives for the preprocessor statement to enum value in led_control.h

DRIVER_HALT is a driver state that was originally
defined as a #define statement. This patch moves
it to the LedEvents type as an enumerated
value for the purpose of removing a compile time warning:

drivers/staging/bcm/led_control.c: In function ‘LEDControlThread’:
drivers/staging/bcm/led_control.c:817:3: warning: case value ‘255’ not in enumerated type ‘LedEventInfo_t’ [-Wswitch]

Signed-off-by: Kevin McKinney <klmckinney1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>