/proc/sys/net/core/optmem_max on armv7l

Hello together,

I just noticed, there is a difference in the default value of
`/proc/sys/net/core/optmem_max` on armv7l:

On all arches it is 20480, but on armv7l it is 10240.

Is there any specific reason for limiting the maximum ancillary buffer
size allowed per socket on this arch?