Enhance UVC decriptors and example

[hathach]

Describe the PR
UVC (as well as UAC) has a sophisticated configuration descriptor depending on user application, which make defining template macros rather difficult. I have update video_capture example to use custom struct to define uvc configuration descriptor. In my opinion, it make thing a bit clearer and easier to customize and troubleshoot descriptor typo/errors.

I also rename some of the video descritpor add several variant of struct/typedef with different number of trailing object. Since C only allow flexible array as the last member of a struct (custom configuration requires as few instance of these struct). There is still more update but @kkitayam please review and let me know what do you think

#define tusb_desc_video_control_header_nitf_t(_nitf) \
  struct TU_ATTR_PACKED { \
    uint8_t  bLength; \
    uint8_t  bDescriptorType; \
    uint8_t  bDescriptorSubType; \
    uint16_t bcdUVC; \
    uint16_t wTotalLength; \
    uint32_t dwClockFrequency; /* deprecated */ \
    uint8_t  bInCollection; \
    uint8_t  baInterfaceNr[_nitf]; \
  }

typedef tusb_desc_video_control_header_nitf_t()  tusb_desc_video_control_header_t;
typedef tusb_desc_video_control_header_nitf_t(1) tusb_desc_video_control_header_1itf_t;
typedef tusb_desc_video_control_header_nitf_t(2) tusb_desc_video_control_header_2itf_t;
typedef tusb_desc_video_control_header_nitf_t(3) tusb_desc_video_control_header_3itf_t;
typedef tusb_desc_video_control_header_nitf_t(4) tusb_desc_video_control_header_4itf_t;

[kkitayam]

As you said, I agree that defining descriptors using macros was very difficult. I think the method you suggested is very wonderful. Above all, I think it is good that the compiler’s type checking can be used, so that errors can be detected earlier.

[hathach]

As you said, I agree that defining descriptors using macros was very difficult. I think the method you suggested is very wonderful. Above all, I think it is good that the compiler’s type checking can be used, so that errors can be detected earlier.

thank you very much for your review, glad that makes sense. The macro template in example will be still kept there for referennce