ipa: ipu3: Fix minor Doxygen issues in IPAFrameContext

The IPAFrameContext documentation has a spurious Doxygen \struct
statement that is not needed, and uses a \struct instead of a \var in
another location. Fix both issues. This doesn't cause any change in the
generated documentation.

Note that the Doxygen output for IPAFrameContext is incorrect,
documentation is missing for all members. This is caused by using "."
instead of "::" in our documentation, which we currently do because the
correct syntax produces Doxygen warnings (and still incorrect output).
See https://github.com/doxygen/doxygen/issues/9343.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/ipa/ipu3/ipa_context.cpp

@@ -75,7 +75,6 @@ namespace libcamera::ipa::ipu3 {
  * \var IPAActiveState::af
  * \brief Context for the Automatic Focus algorithm
  *
- * \struct IPAActiveState::af
  * \var IPAActiveState::af.focus
  * \brief Current position of the lens
  *
@@ -134,7 +133,7 @@ namespace libcamera::ipa::ipu3 {
  * \var IPAActiveState::awb
  * \brief Context for the Automatic White Balance algorithm
  *
- * \struct IPAActiveState::awb.gains
+ * \var IPAActiveState::awb.gains
  * \brief White balance gains
  *
  * \var IPAActiveState::awb.gains.red