MAINTAINERS: Update maintainer for SDHCI Broadcom BRCMSTB driver

Taking over as upstream maintainer for Broadcom SDHCI
driver from Al Cooper.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20221202212119.43214-1-kdasu.kdev@gmail.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>