Add Praline P1/P2 support to hackrf_clock

[mossmann]

What feature would you like to see and why?

P1 and P2 multiplexers can be controlled with hackrf_debug, but we would also like more user-friendly options in hackrf_clock. This should support basic CLKIN, CLKOUT, and trigger IO functions.

[antoinevg]

What else do we need in addition to:

hackrf/host/hackrf-tools/src/hackrf_clock.c

Lines 294 to 297 in 0ea91e2

	printf("\t-1, --p1 <signal>: select the HackRF Pro P1 SMA connector signal (default: clkin)\n");
	printf("\tone of: clkin, trigger_in, trigger_out, p22_clkin, pps_out, aux_clk1, aux_clk2, off\n");
	printf("\t-2, --p2 <signal>: select the signal for the HackRF Pro P2 SMA connector (default: clkout)\n");
	printf("\tone of: clkout, trigger_in, trigger_out\n");