arm: dts: stm32mp15: alignment with v5.17

Device tree alignment with Linux kernel v5.17-rc1
- ARM: dts: stm32: add pull-up to USART3 and UART7 RX pins
  on STM32MP15 DKx boards
- ARM: dts: stm32: clean uart4_idle_pins_a node for stm32mp15
- ARM: dts: stm32: tune the HS USB PHYs on stm32mp15xx-dkx
- ARM: dts: stm32: tune the HS USB PHYs on stm32mp157c-ev1
- ARM: dts: stm32: fix stusb1600 pinctrl used on stm32mp157c-dk

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>