arm64: defconfig: Do not override the MTK_PMIC_WRAP symbol

arm64: defconfig: Do not override the MTK_PMIC_WRAP symbol

Commit 'fbbe38309d56 ("arm64: defconfig: Allow mt8173-based boards to boot
from usb")' added the MTK_PMIC_WRAP config built-in. It needs to be
built-in in order to be able to boot from USB or the MMC without needing
a ramdisk, but that symbol was already defined as a module so now we are
getting the following warning:

  arch/arm64/configs/defconfig:996:warning: override: reassigning to symbol MTK_PMIC_WRAP

Remove the MTK_PMIC_WRAP=m from the defconfig to remove the error.

Fixes: fbbe38309d56 ("arm64: defconfig: Allow mt8173-based boards to boot from usb")
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20210423075201.2616023-1-enric.balletbo@collabora.com
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>