mmc: sdhci-of-k1: make register definition vendor specific

mmc: sdhci-of-k1: make register definition vendor specific

Making register definition less generic which will potentially have
less collision with other files.

Add SpacemiT vendor prefix to K1 SoC SDHC register definitions,
also improve the BIT definitions to reflect them more SDHC specific.

Note, there should be no functional changes introduced in this commit.

Signed-off-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/r/20250523-21-k1-sdhci-v1-1-9f293116a7e7@gentoo.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>