wifi: libertas: fix config name in dependency for SDIO support

Commit 4b478bf6 ("wifi: libertas: drop 16-bit PCMCIA support") reworks
the dependencies for config LIBERTAS, and adds alternative dependencies for
USB, SDIO and SPI.

The config option SDIO however does not exist in the kernel tree. It was
probably intended to refer to the config option MMC, which represents
"MMC/SD/SDIO card support" and is used as dependency by various other
drivers that use SDIO.

Fix the dependency to the config option MMC for declaring the requirement
on provision of SDIO support.

Fixes: 4b478bf6 ("wifi: libertas: drop 16-bit PCMCIA support")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231122083047.12774-1-lukas.bulwahn@gmail.com