loongarch: Add to build system

This patch adds LoongArch to the GRUB build system and various tools,
so GRUB can be built on LoongArch as a UEFI application.

Signed-off-by: Zhou Yang <zhouyang@loongson.cn>
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

include/grub/efi/api.h

@@ -1797,7 +1797,7 @@ typedef struct initrd_media_device_path initrd_media_device_path_t;
 
 #if (GRUB_TARGET_SIZEOF_VOID_P == 4) || defined (__ia64__) \
   || defined (__aarch64__) || defined (__MINGW64__) || defined (__CYGWIN__) \
-  || defined(__riscv)
+  || defined(__riscv) || defined (__loongarch__)
 
 #define efi_call_0(func)		(func)()
 #define efi_call_1(func, a)		(func)(a)

include/grub/util/install.h

@@ -107,6 +107,7 @@ enum grub_install_plat
     GRUB_INSTALL_PLATFORM_I386_XEN_PVH,
     GRUB_INSTALL_PLATFORM_ARM64_EFI,
     GRUB_INSTALL_PLATFORM_ARM_COREBOOT,
+    GRUB_INSTALL_PLATFORM_LOONGARCH64_EFI,
     GRUB_INSTALL_PLATFORM_RISCV32_EFI,
     GRUB_INSTALL_PLATFORM_RISCV64_EFI,
     GRUB_INSTALL_PLATFORM_MAX