Remove the internal-only attribute from ruby_reset_timezone()

The #ifdef is currently not taken because include/ruby/backward.h is
not included at this point. The attribute is unnecessary in an internal
header, so remove it.

Author: rhenium

internal/time.h

@@ -28,9 +28,6 @@ struct timeval rb_time_timeval(VALUE);
 RUBY_SYMBOL_EXPORT_BEGIN
 /* time.c (export) */
 void ruby_reset_leap_second_info(void);
-#ifdef RBIMPL_ATTR_DEPRECATED_INTERNAL_ONLY
-RBIMPL_ATTR_DEPRECATED_INTERNAL_ONLY()
-#endif
 void ruby_reset_timezone(const char *);
 RUBY_SYMBOL_EXPORT_END