Bluetooth: Reorder GATT struct members to avoid padding

This makes sure the bigger members are always list first in non-packed
struct to minimize the use of padding for alignment by the compiler.

Change-Id: I64419e9b27f4e7d3abb4eeb0ef2a88beda5b22e3
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>