STM32H7 BSP: Add SDMMC-driver (Note: Extends libbsd media01)

[Christian Mauderer]

Hello,

the patch set for RTEMS, libbsd and docs add a SDMMC driver for STM32H7
to libbsd. Note that I added the md5 command to media01 which is useful
when testing storage devices. Beneath that I added a command that can
fill a disk or a file with an incrementing number which - again - can be
useful for testing storage media. The later command is only added to
media01 because I don't think it's a useful general purpose command but
rather a pure test command.

Patches belonging to this set:

RTEMS:
[PATCH rtems 1/2] stm32h7: Add SDMMC modules to clock.
[PATCH rtems 2/2] stm32h7: Add init for sdmmc pins.

libbsd:
[PATCH rtems-libbsd 1/3] testsuite/media01: Enable md5 command
[PATCH rtems-libbsd 2/3] testsuite/media01: Add pattern test.
[PATCH rtems-libbsd 3/3] STM32H7: Add SDMMC driver

docs:
[PATCH rtems-docs] user/bsps: Add STM32H7 SDMMC driver

Best regards

Christian