i2c: i2c-qcom-geni: Simplify irq handler

We don't need to use goto here, we can just collapse the if statement
and goto chain into multiple branches and then combine some duplicate
completion calls into one big if statement. Let's do it to clean up code
some more.

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Alok Chauhan <alokc@codeaurora.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>