e2fsprogs: the max length of debugfs argument is too short

e2fsprogs: the max length of debugfs argument is too short

The max length of debugfs argument is 256 which is too short, the
arguments are two paths, the PATH_MAX is 4096 according to
/usr/include/linux/limits.h, so use BUFSIZ (which is 8192 on Linux
systems), that's also what the ss library uses.

This patch has been reviewed by the linux-ext4 mailing list, but isn't
merged atm.

[YOCTO #3848]

(From OE-Core rev: a916a127768291ca7c614976e05c90153fec2956)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>