move PLL reset code from clocks driver to pll driver (#110)

* move PLL reset code from clocks driver to pll driver

* Don't clear PLL PWR/FBDIV after reset as unnecessary. Call out in runtime.c why USB/syscfg aren't reset.

Co-authored-by: Peter Lawrence <12226419+majbthrd@users.noreply.github.com>
Co-authored-by: Luke Wren <wren6991@gmail.com>

src/rp2_common/pico_runtime/runtime.c

@@ -63,10 +63,13 @@ void runtime_init(void) {
     // Reset all peripherals to put system into a known state,
     // - except for QSPI pads and the XIP IO bank, as this is fatal if running from flash
     // - and the PLLs, as this is fatal if clock muxing has not been reset on this boot
+    // - and USB, syscfg, as this disturbs USB-to-SWD on core 1
     reset_block(~(
             RESETS_RESET_IO_QSPI_BITS |
             RESETS_RESET_PADS_QSPI_BITS |
             RESETS_RESET_PLL_USB_BITS |
+            RESETS_RESET_USBCTRL_BITS |
+            RESETS_RESET_SYSCFG_BITS |
             RESETS_RESET_PLL_SYS_BITS
     ));