We should allow RXDMA only if the reset was really successful, so clear
the flag after the reset call.

Fixes: 0e864b55 ("i2c: rcar: reset controller is mandatory for Gen3+")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>