mediatek: enable multi-core scheduling

Set CONFIG_SCHED_MC in config-5.15 to have make the scheduler aware
of shared caches.

Reported-by: Rui Salvaterra <[email protected]>
Signed-off-by: Daniel Golle <[email protected]>

target/linux/mediatek/mt7622/config-5.15

@@ -384,6 +384,7 @@ CONFIG_RTC_DRV_MT7622=y
 CONFIG_RTC_I2C_AND_SPI=y
 CONFIG_RTL8367S_GSW=y
 CONFIG_RWSEM_SPIN_ON_OWNER=y
+CONFIG_SCHED_MC=y
 CONFIG_SCSI=y
 CONFIG_SCSI_COMMON=y
 # CONFIG_SECTION_MISMATCH_WARN_ONLY is not set