CONFIG_STM32F7_LCD_BACKLIGHT is not defined by any Kconfig, so the LTDC
backlight control is dead code. CONFIG_STM32F7_PLLSAI and
CONFIG_STM32F7_PLLI2S are defined by the board.h files, and the common
SPI test helper names its mode macros CONFIG_STM32F7_SPIx_TEST_MODE.
Use the common CONFIG_STM32_* names everywhere.
Also drop the misspelled CONFIG_STM32F7_STM33F75XX from the DMA chip
check, which already tests CONFIG_STM32_STM32F75XX.
The CAN section of the STM32F7 documentation names the options
CONFIG_STM32F7F7_CANx, which has a duplicated family prefix and never
existed. Use the common names there too.
Signed-off-by: raiden00pl <raiden00@railab.me>
Assisted-by: Claude Code