inode.7: STANDARDS: Remove bogus recommendation

inode.7: STANDARDS: Remove bogus recommendation

'blkcnt_t' is defined in <sys/types.h>, per POSIX.1-2001, as
blkcnt_t(3type) documents.  Also, it doesn't need any ftm(7) to be
defined, AFAICS:

    $ cat blkcnt_t.c
    #include <sys/types.h>

    int main(void) {
        blkcnt_t x;

        return x = 0;
    }
    $ cc -Wall -Wextra blkcnt_t.c
    $

Signed-off-by: Alejandro Colomar <alx@kernel.org>