mmc: sdhci-esdhc: update contact email

The 'pengutronix' address is defunct for years. Use the proper contact
address.

Signed-off-by: Wolfram Sang <wsa@kernel.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200502142840.19418-1-wsa@kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>