hooks/{archiso,archiso_pxe_http}: replace mkdir commands with mount's --mkdir option

util-linux 2.38 added a --mkdir option to mount that creates the mountpoint if it does not exist.

changed milestone to %v63

requested review from @dvzrv

assigned to @nl6720

approved this merge request

Thanks! That looks great! :)

merged

mentioned in merge request !21 (merged)