diag: Change to update the range correctly on a range mismatch

Setting message masks with tools outside of the initial range
causes a reallocation of the structure with the wrong size.
This change updates the sizes to the correct values.

Change-Id: I8bb0d0b77cd4d2417b10345b6e4b09ff29ba5f8c
Signed-off-by: Christopher Lew <clew@codeaurora.org>