VLD2/VST2 fixes & CSDB warning removal
VLD2/VST2 "single lane" register increments were off-by-one, resulting in nonsense like VLD2.8 {D0[3],D0[3]},[R0]
CSDB "ARMv8.4 or later" warning removed; according to Arm, the instruction works as far back as ARMv4 (and due to its nature, likely as far back as ARMv2). See the commit message for more info.