powerpc: configs: Cleanup old Kconfig options

CONFIG_ENABLE_WARN_DEPRECATED is gone since
commit 771c0353 ("deprecate the '__deprecated' attribute warnings
entirely and for good").

CONFIG_IOSCHED_DEADLINE and CONFIG_IOSCHED_CFQ are gone since
commit f382fb0b ("block: remove legacy IO schedulers").

The IOSCHED_DEADLINE was replaced by MQ_IOSCHED_DEADLINE and it will be
now enabled by default (along with MQ_IOSCHED_KYBER).

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200130195223.3843-1-krzk@kernel.org