[fidl][sysinfo] Rename ZBI_BOARD_NAME_LEN

It clashes with the macro in zbi/image.h.

MAC-180

Test: Ran "zircon_guest" on a VIM2.
Change-Id: I42a1e17b81da1f187a679fad82ad04364f256d75
diff --git a/system/fidl/fuchsia-sysinfo/sysinfo.fidl b/system/fidl/fuchsia-sysinfo/sysinfo.fidl
index ff229e9..4cfd790 100644
--- a/system/fidl/fuchsia-sysinfo/sysinfo.fidl
+++ b/system/fidl/fuchsia-sysinfo/sysinfo.fidl
@@ -6,7 +6,7 @@
 
 using zx;
 
-const uint8 ZBI_BOARD_NAME_LEN = 32;
+const uint8 SYSINFO_BOARD_NAME_LEN = 32;
 
 enum InterruptControllerType {
     UNKNOWN = 0;
@@ -31,7 +31,7 @@
     3: GetHypervisorResource() -> (zx.status status, handle<resource>? resource);
 
     // Return the board name for the platform we are running on.
-    4: GetBoardName() -> (zx.status status, string:ZBI_BOARD_NAME_LEN? name);
+    4: GetBoardName() -> (zx.status status, string:SYSINFO_BOARD_NAME_LEN? name);
 
     // Return interrupt controller information.
     5: GetInterruptControllerInfo() -> (zx.status status, InterruptControllerInfo? info);