default or selected kernelversion does not have config value CONFIG_VIDEO_ALLOW_V4L1.
Result is shown for kernelversion 5.4.69

Enable Video For Linux API 1 (DEPRECATED)


Linux Kernel Configuration
└─>Device Drivers
└─>Multimedia support
└─>Enable Video For Linux API 1 (DEPRECATED)
In linux kernel since version 2.6.26 (release Date: 2008-07-13)  
Enables drivers based on the legacy V4L1 API.

This api were developed to be used at Kernel 2.2 and 2.4, but
lacks support for several video standards. There are several
drivers at kernel that still depends on it.

If you are unsure as to whether this is required, answer Y.