util-linux: Use SYS_getrandom in randutils.c
The getrandom syscall is not hanging at bootup any more if there is
not enough entropy. This was fixed upstream in 2018 in commit:
https://github.com/util-linux/util-linux/commit/a9cf659e0508c1f56813a7d74c64f67bbc962538
This OpenWrt patch is not needed any more.
This reverts commit e64463ebde55 ("util-linux: avoid using the getrandom syscall")
Signed-off-by: Hauke Mehrtens <[email protected]>