mlx90640: Add hardware/clocks for set_sys_clock_khz.

examples/breakout_mlx90640/CMakeLists.txt

@@ -6,7 +6,7 @@ add_executable(
 )
 
 # Pull in pico libraries that we need
-target_link_libraries(${OUTPUT_NAME} pico_stdlib mlx90640 hub75_legacy hardware_vreg)
+target_link_libraries(${OUTPUT_NAME} pico_stdlib mlx90640 hub75_legacy hardware_vreg hardware_clocks)
 
 # create map/bin/hex file etc.
 pico_add_extra_outputs(${OUTPUT_NAME})

examples/breakout_mlx90640/demo.cpp

@@ -1,5 +1,6 @@
 #include "pico/stdlib.h"
 #include "hardware/vreg.h"
+#include "hardware/clocks.h"
 #include "stdio.h"
 
 #include <algorithm>