arch: fix neon feature detection

The fread function returns the number of elements read, not the number
of bytes.

Introduced by 1cef8339f7a2a503327c20c014e696c91d36281e , after giant.

Signed-off-by: Loic Dachary <ldachary@redhat.com>
https://www.gnu.org/software/libc/manual/html_node/Block-Input_002fOutput.html - so you want to read 1 object of sizeof(entry) and then you are cheking if read is equal or not to 1.

:+1: