remove alloc_page from dm-emc.c

Hey Lars,

Here is what I meant. A Page for just something around 8-16 bytes seems wasteful. Plus there is no reserve.

If you have to end up setting more bits maybe it is better to preallocate a command per device at create time, or maybe since there are four different combos I should have done it with this patch?

This was made against 2.6.12-rc2. Only compile tested.

Mike