Port USDHC1 (eMMC) driver to the i.MX95 FRDM EVK board:
- Create imx95_pinmux.h with SD1/USDHC1 pin definitions
- Add USDHC1 pin macros to board.h
- Create board-level imx9_usdhc.c glue code
- Update imx9_bringup.c with DMA allocator and USDHC init
- Add SCMI clock guards in imx9_usdhc.c (imx95 clock roots
are owned by System Manager, direct CCM writes are no-ops)
- Fix CCM_CR_USDHC2 copy-paste bug to CCM_CR_USDHC1
Signed-off-by: buxiasen <buxiasen@xiaomi.com>