turn 'switch' errors into warnings to notify about unhandled values

Many sections of the code rely on switches over the ControlType enum to
handle the different libcamera control types. When newer enum values are
added with newer versions of libcamera, the 'switch' errors (-Wall) will
prevent compilation even though the node will continue to work without
supporting the new types.

Relax this by turning all 'switch' errors into warnings again to notify
the developer and implement support for these new type enum values later.

CMakeLists.txt

@@ -5,6 +5,7 @@ set(CMAKE_CXX_STANDARD 17)
 
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(-Wall -Wextra -Wpedantic -Werror)
+  add_compile_options(-Wno-error=switch)
   add_link_options("-Wl,-z,relro,-z,now,-z,defs")
 endif()