riscv: fix accessing 8-byte variable from RV32

riscv: fix accessing 8-byte variable from RV32

[ Upstream commit dbee9c9c45846f003ec2f819710c2f4835630a6a ]

A memory save operation to 8-byte variable in RV32 is divided into
two sw instructions in the put_user macro.  The current fixup returns
execution flow to the second sw instead of the one after it.

This patch fixes this fixup code according to the load access part.

Signed-off-by: Alan Kao<alankao@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>