staging: greybus: firmware: Remove trailing semicolon from FW_TIMEOUT_DEFAULT

Fixes checkpatch warning:
  macros should not use a trailing semicolon

Signed-off-by: Michael Sartain <mikesart@fastmail.com>
Acked-by: Viresh Kumar <viresh.kumar at linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>