tools/nolibc: make dev_t 64 bits wide

tools/nolibc: make dev_t 64 bits wide

statx() returns both 32-bit minor and major numbers. For both of them to
fit into the 'dev_t' in 'struct stat', that needs to be 64 bits wide.

The other uses of 'dev_t' in nolibc are makedev() and friends and
mknod(). makedev() and friends are going to be adapted in an upcoming
commit and mknod() will silently truncate 'dev_t' to 'unsigned int' in
the kernel, similar to other libcs.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260404-nolibc-makedev-v2-4-456a429bf60c@weissschuh.net