tegra: remove some cruft from CONFIG_EXTRA_ENV_SETTINGS

tegra: remove some cruft from CONFIG_EXTRA_ENV_SETTINGS

console isn't used by anything, and the kernel should be set appropriately
by whatever script is booting the kernel, not imposed by the bootloader.

mem might be useful, but the current value is pretty bogus, since it
includes nvmem options that make no sense for an upstream kernel, and
equally should not be required for any downstream kernel. Either way, this
is also best left to the kernel boot script.

smpflag isn't used by anything, and again was probably intended to be a
kernel command-line option better set by the kernel boot script.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>