i2c: stm32: Do not check for 0 return after calling platform_get_irq()

It is not possible for platform_get_irq() to return 0. Use the
return value from platform_get_irq().

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Acked-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/20230731112755.1943630-1-ruanjinjie@huawei.com


Signed-off-by: Andi Shyti <andi.shyti@kernel.org>