lfbgrid: Make pointer size testing not arch name dependent

apps/lfbgrid.c

@@ -51,11 +51,9 @@ draw_boxes(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop)
 	UINTN NumPixels;
 	UINT32 *PixelBuffer;
 	UINT32 CopySize, BufferSize;
-#if defined(__x86_64__) || defined(__aarch64__) || \
-    (defined (__riscv) && __riscv_xlen == 64) || \
-    defined(__loongarch64)
+#if __SIZEOF_POINTER__ == 8
 	UINT64 FrameBufferAddr;
-#elif defined(__i386__) || defined(__arm__)
+#elif __SIZEOF_POINTER__ == 4
 	UINT32 FrameBufferAddr;
 #else
 #error YOUR ARCH HERE
@@ -116,11 +114,9 @@ draw_boxes(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop)
 			Print(L"No linear framebuffer on this device.\n");
 			return;
 		}
-#if defined(__x86_64__) || defined(__aarch64__) || \
-    (defined (__riscv) && __riscv_xlen == 64) || \
-    defined(__loongarch64)
+#if __SIZEOF_POINTER__ == 8
 		FrameBufferAddr = (UINT64)gop->Mode->FrameBufferBase;
-#elif defined(__i386__) || defined(__arm__)
+#elif __SIZEOF_POINTER__ == 4
 		FrameBufferAddr = (UINT32)(UINT64)gop->Mode->FrameBufferBase;
 #else
 #error YOUR ARCH HERE