various: fix variable and function declarations [smatch scan]

various: fix variable and function declarations [smatch scan]

disk-utils/fsck.minix.c:511:9: warning: mixing declarations and code
fdisks/sfdisk.c:982:5: warning: mixing declarations and code
fdisks/sfdisk.c:1254:5: warning: mixing declarations and code
fdisks/sfdisk.c:1564:5: warning: mixing declarations and code
lib/mbsalign.c:279:7: warning: mixing declarations and code
libblkid/src/devname.c:378:17: warning: mixing declarations and code
libfdisk/src/alignment.c:219:9: warning: mixing declarations and code
term-utils/wall.c:111:9: warning: mixing declarations and code
text-utils/col.c:418:19: warning: non-ANSI function declaration of function 'flush_blanks'
text-utils/col.c:553:12: warning: non-ANSI function declaration of function 'alloc_line'
text-utils/rev.c:105:9: warning: mixing declarations and code
text-utils/tailf.c:245:9: warning: mixing declarations and code

Signed-off-by: Sami Kerola <kerolasa@iki.fi>