usb_cdc: Only call bootloader_request() if CONFIG_HAVE_BOOTLOADER_REQUEST

Check for the build symbol prior to calling bootloader_request().
Enable the build symbol on rp2040, atsam, and atsamd chips.

This also enables serial bootloader requsts on rp2040, atsam, and
atsamd.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/generic/usb_cdc.c

@@ -446,6 +446,8 @@ static uint8_t line_control_state;
 static void
 check_reboot(void)
 {
+    if (!CONFIG_HAVE_BOOTLOADER_REQUEST)
+        return;
     if (line_coding.dwDTERate == 1200 && !(line_control_state & 0x01))
         // A baud of 1200 is an Arduino style request to enter the bootloader
         bootloader_request();