lantiq: ase: cleanup kernel config

The subtarget kernel config options CONFIG_CC_OPTIMIZE_FOR_SIZE and
CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK are already set by the target or
global kernel config.

Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/lantiq/ase/config-default

@@ -1,5 +1,4 @@
 CONFIG_ADM6996_PHY=y
-CONFIG_CC_OPTIMIZE_FOR_SIZE=y
 CONFIG_CPU_MIPS32_R1=y
 # CONFIG_CPU_MIPS32_R2 is not set
 CONFIG_CPU_MIPSR1=y
@@ -9,7 +8,6 @@ CONFIG_FIRMWARE_IN_KERNEL=y
 CONFIG_FIRMWARE_MEMMAP=y
 CONFIG_GPIO_GENERIC=y
 CONFIG_GPIO_GENERIC_PLATFORM=y
-CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK=y
 # CONFIG_ISDN is not set
 # CONFIG_LBDAF is not set
 CONFIG_LEDS_TRIGGER_HEARTBEAT=y