octeontx2-af: Free NIX_AF_INT_VEC_GEN irq

octeontx2-af: Free NIX_AF_INT_VEC_GEN irq

Due to the incorrect initial vector number in
rvu_nix_unregister_interrupts(), NIX_AF_INT_VEC_GEN is not
geeting free. Fix the vector number to include NIX_AF_INT_VEC_GEN
irq.

Fixes: 5ed66306eab6 ("octeontx2-af: Add devlink health reporters for NIX")
Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250327094054.2312-1-gakula@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>