From clang-13:
hw/pci-host/pnv_phb4.c:375:18: error: variable 'v' set but not used \
    [-Werror,-Wunused-but-set-variable]

It's pretty clear that we meant to write back 'v' after
all that computation and not 'val'.

Acked-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>