__GPIOI_CLK_ENABLE is defined in hal/l4/inc/Legacy/stm32_hal_legacy.h
as __HAL_RCC_GPIOI_CLK_ENABLE, and that latter macro is not defined
anywhere else (because the L4 does not have port GPIOI).  So the test
for GPIOI is needed, along with the test for the CLK_ENABLE macro.