Revert "update defconfig, remove some debug stuff, EXT2, reduce LOG_BUF size,..."

This reverts commit 811b5e737d9119bb3b94079d34f5bf631cd573f1.
Revert "completely disable MMC_CAP_ERASE (paranoid, no MMC_CAP_ERASE in
mach-u1.c)"

This reverts commit e4e31015d53c6bb6a3f50766b32e62cdd6f3b419.