logging: Simplify sim logging
logging: Simplify sim logging

Instead of a separate invocation of printf to print the trailing
newline, use some modern cpp trickery to expand the format string
explicitly.  The ## will remove the preceding comma of the argument list
if empty.

tamban01/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot,tamban01/mcuboot,runtimeco/mcuboot,tamban01/mcuboot,utzig/mcuboot,tamban01/mcuboot,runtimeco/mcuboot,ATmobica/mcuboot,runtimeco/mcuboot,runtimeco/mcuboot,utzig/mcuboot,tamban01/mcuboot,runtimeco/mcuboot,utzig/mcuboot,ATmobica/mcuboot,utzig/mcuboot,ATmobica/mcuboot,utzig/mcuboot