Enable dm-cache for kernel 3.9+

[Vincent Stehlé]

Hi,

While trying kernel from [1] I noticed that CONFIG_DM_CACHE was not enabled.

Could someone enable CONFIG_DM_CACHE for the future kernel builds, please?

FYI, dm-cache is a new dm target merged in kernel 3.9, which allows to
use an SSD as a hard disk cache, for example (see [2]).

(I already asked this question to the IRC channel #ubuntu-kernel, but as
nobody answered I repost to the ml.)

Best regards,

V.

[1] http://kernel.ubuntu.com/~kernel-ppa/mainline/daily/current/
[2]
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/device-mapper/cache.txt?id=refs/tags/v3.9-rc8