libcamera: base: utils: Simplify hex adaptor

The libcamera hex string adaptor specifies and casts each type
specifically to map the size of each type.

This needlessly repeats itself for each type and further more has a bug
with signed integer extension which causes values such as 0x80 to be
printed as 0xffffffffffffff80 instead.

Remove the template specialisations for each type, and unify with a
single templated constructor of the struct hex trait.

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

src/libcamera/base/utils.cpp

@@ -187,7 +187,8 @@ std::string time_point_to_string(const time_point &time)
 }
 
 std::basic_ostream<char, std::char_traits<char>> &
-operator<<(std::basic_ostream<char, std::char_traits<char>> &stream, const _hex &h)
+details::operator<<(std::basic_ostream<char, std::char_traits<char>> &stream,
+		    const details::hex &h)
 {
 	stream << "0x";