Merge tag 'u-boot-stm32-20230816' of https://source.denx.de/u-boot/custodians/u-boot-stm

DHSOM: Power cycle Buck3 in reset
DHCOM: Switch DWMAC RMII clock to MCO2
stm32f746: fix display pinmux
stm32mp: psci: Inhibit PDDS because CSTBYDIS is set
stm32mp1: DT alignment with v6.4
stm32mp1: add splashscreen with STMicroelectronics logo
stm32mp1: clk: remove error for disabled clock in stm32mp1_clk_get_parent
serial: stm32: Extend TC timeout