Set continuous serirq

Change-Id: I2c099901a1e7b8b1402b5261c2a5c5a1685ec69f

src/mainboard/system76/galp5/Kconfig

@@ -18,6 +18,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select MAINBOARD_HAS_TPM2
 	select NO_UART_ON_SUPERIO
 	select PCIEXP_HOTPLUG
+	select SERIRQ_CONTINUOUS_MODE
 	select SOC_INTEL_TIGERLAKE
 	select SOC_INTEL_COMMON_BLOCK_HDA
 	select SOC_INTEL_COMMON_BLOCK_HDA_VERB

src/soc/intel/tigerlake/Kconfig

@@ -216,4 +216,10 @@ config SOC_INTEL_TIGERLAKE_DEBUG_CONSENT
 config PRERAM_CBMEM_CONSOLE_SIZE
 	hex
 	default 0x2000
+
+config SERIRQ_CONTINUOUS_MODE
+	bool
+	help
+	  If you set this option to y, the serial IRQ machine will be
+	  operated in continuous mode.
 endif