libcamera: utils: Only enable utils::hex() for integer arguments

The utils::hex() function is defined as a function template that has
implementations for integer arguments only. When given a different
argument type, the compiler will not catch the issue, but linking will
fail:

src/libcamera/libcamera.so.p/camera_sensor.cpp.o: in function `libcamera::CameraSensor::validateSensorDriver()':
camera_sensor.cpp:(.text+0x1e6b): undefined reference to `libcamera::utils::_hex libcamera::utils::hex<libcamera::ControlId const*>(libcamera::ControlId const*, unsigned int)'

Move the failure to compilation time by enabling the function for
integer arguments only. This provides better diagnostics:

../../src/libcamera/camera_sensor.cpp: In member function ‘int libcamera::CameraSensor::validateSensorDriver()’:
../../src/libcamera/camera_sensor.cpp:199:77: error: no matching function for call to ‘hex(const libcamera::ControlId*&)’

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

0 files changed, 0 insertions, 0 deletions