ARM: 9200/1: spectre-bhb: avoid cross-subsection jump using a numbered label

In order to minimize potential confusion regarding numbered labels
appearing in a different order in the assembler output due to the use of
subsections, use a named local label to jump back into the vector
handler code from the associated loop8 mitigation sequence.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>