msp430fr5994 arch.sleep_ms: fix max sleey duration documentation

volatile bool sleep_done = false;

// max delay: 2621 ms

// max delay: 262 ms @ 16 MHz

// max delay: 524 ms @  8 MHz

void Arch::sleep_ms(unsigned int const ms)

{

	sleep_done = false;

#if F_CPU == 16000000UL

	TA3CTL = TASSEL__SMCLK | ID__8; // /8

	TA3EX0 = 7; // /8 -> /64 (250 kHz)

	TA3CCR0 = ms * 250;

#elif F_CPU == 8000000UL

	TA3CTL = TASSEL__SMCLK | ID__8; // /8

	TA3EX0 = 3; // /4 -> /32 (250 kHz)

	TA3EX0 = 7; // /8 -> /64 (125 kHz)

	TA3CCR0 = ms * 125;

#elif F_CPU == 4000000UL

	TA3CTL = TASSEL__SMCLK | ID__4; // /4

	TA3EX0 = 3; // /4 -> /16 (250 kHz)

	TA3CTL = TASSEL__SMCLK | ID__8; // /8

	TA3EX0 = 3; // /4 -> /32 (125 kHz)

	TA3CCR0 = ms * 125;

#elif F_CPU == 1000000UL

	TA3CTL = TASSEL__SMCLK | ID__1; // /1

	TA3EX0 = 3; // /4 -> /4 (250 kHz)

	TA3CTL = TASSEL__SMCLK | ID__8; // /8

	TA3EX0 = 0; // /1 -> /8 (125 kHz)

	TA3CCR0 = ms * 125;

#else

#error Unsupported F_CPU

#endif /* F_CPU */

	TA3CCR0 = ms * 250;

	TA3CCTL0 = CCIE;

	TA3CTL |= MC__UP | TACLR;

	while (!sleep_done) {