LoongArch: Enable ACPI BGRT handling

Add ACPI BGRT support on LoongArch so it can display image provied by
acpi table at boot stage and switch to graphical UI smoothly.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: bibo-mao

arch/loongarch/kernel/acpi.c

@@ -9,6 +9,7 @@
 
 #include <linux/init.h>
 #include <linux/acpi.h>
+#include <linux/efi-bgrt.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/memblock.h>
@@ -212,6 +213,9 @@ void __init acpi_boot_table_init(void)
 	/* Do not enable ACPI SPCR console by default */
 	acpi_parse_spcr(earlycon_acpi_spcr_enable, false);
 
+	if (IS_ENABLED(CONFIG_ACPI_BGRT))
+		acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt);
+
 	return;
 
 fdt_earlycon:

drivers/acpi/Kconfig

@@ -451,7 +451,7 @@ config ACPI_HED
 
 config ACPI_BGRT
 	bool "Boottime Graphics Resource Table support"
-	depends on EFI && (X86 || ARM64)
+	depends on EFI && (X86 || ARM64 || LOONGARCH)
 	help
 	  This driver adds support for exposing the ACPI Boottime Graphics
 	  Resource Table, which allows the operating system to obtain