BaseTools: Update GenFw/GenFv to support LoongArch platform.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4053

C code changes for building EDK2 LoongArch platform.

For definitions of PE/COFF and LOONGARCH relocation types, see the
"Machine Types" and "Basic Relocation Types" sections of this URL for
LOONGARCH values:
https://docs.microsoft.com/en-us/windows/win32/debug/pe-format

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Yuwei Chen <yuwei.chen@intel.com>

Signed-off-by: Chao Li <lichao@loongson.cn>
Co-authored-by: Dongyan Qian <qiandongyan@loongson.cn>
Co-authored-by: Baoqi Zhang <zhangbaoqi@loongson.cn>
Co-authored-by: Yang Zhou <zhouyang@loongson.cn>
Co-authored-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>

BaseTools/Source/C/Makefiles/header.makefile

@@ -31,6 +31,9 @@ ifndef HOST_ARCH
   ifneq (,$(findstring riscv64,$(uname_m)))
     HOST_ARCH=RISCV64
   endif
+  ifneq (,$(findstring loongarch64,$(uname_m)))
+    HOST_ARCH=LOONGARCH64
+  endif
   ifndef HOST_ARCH
     $(info Could not detected HOST_ARCH from uname results)
     $(error HOST_ARCH is not defined!)
@@ -70,6 +73,9 @@ ARCH_INCLUDE = -I $(MAKEROOT)/Include/AArch64/
 else ifeq ($(HOST_ARCH), RISCV64)
 ARCH_INCLUDE = -I $(MAKEROOT)/Include/RiscV64/
 
+else ifeq ($(HOST_ARCH), LOONGARCH64)
+ARCH_INCLUDE = -I $(MAKEROOT)/Include/LoongArch64/
+
 else
 $(error Bad HOST_ARCH)
 endif