ARM: defconfig: Add IOSCHED_BFQ to the default configs

ARM systems are often memory constrained and more often than not
use slow single-channel storage such as flash memory or MMC/SD-cards.
For any interactive systems (such as mobile phones, tablets,
chromebooks...) the BFQ I/O scheduler will be desireable.

Make sure the BFQ I/O scheduler is available on these systems.

Loongarch, MIPS, m68k, UM and S390 has also enabled BFQ in their
defconfigs, cf commit b495dfed


"um: Cleanup CONFIG_IOSCHED_CFQ" where the motivation is that
it replaces the former CFQ scheduler.

Cc: Paolo Valente <paolo.valente@linaro.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230203140404.1125850-1-linus.walleij@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>