tools/nolibc: move the logic of makedev() and friends into functions

tools/nolibc: move the logic of makedev() and friends into functions

Functions make it easier to keep the input and output types straight and
avoid duplicate evaluations of their arguments.

Also these functions will become a bit more complex to handle full
64-bit 'dev_t' which is easier to read in a function.

Still stay compatible with code which expects these to be macros.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260404-nolibc-makedev-v2-3-456a429bf60c@weissschuh.net