Fix the latest breakage by defining IREE_TIME_NOW_FN

This CL fixes the latest breakage due to the upstream change https://github.com/iree-org/iree/pull/17493

Change-Id: Ib5e983364847fe4ba0cf6a416bf353d1f910b347
diff --git a/cmake/riscv_iree.cmake b/cmake/riscv_iree.cmake
index 3661099..74eea14 100644
--- a/cmake/riscv_iree.cmake
+++ b/cmake/riscv_iree.cmake
@@ -57,6 +57,7 @@
 set(CMAKE_C_EXTENSIONS OFF)     # Force the usage of _ISOC11_SOURCE
 set(CMAKE_SYSTEM_LIBRARY_PATH "${RISCV_TOOLCHAIN_ROOT}/riscv32-unknown-elf/lib")
 set(RISCV_COMPILER_FLAGS "${RISCV_COMPILER_FLAGS} -menable-experimental-extensions -march=rv32imf_zvl512b_zve32x -mabi=ilp32")
+set(RISCV_COMPILER_FLAGS "${RISCV_COMPILER_FLAGS} -DIREE_TIME_NOW_FN=\"\{ return 0; \}\"")
 
 add_compile_definitions(IREE_PLATFORM_GENERIC)
 
diff --git a/cmake/riscv_iree_gcc.cmake b/cmake/riscv_iree_gcc.cmake
index fdc9b6e..6242e69 100644
--- a/cmake/riscv_iree_gcc.cmake
+++ b/cmake/riscv_iree_gcc.cmake
@@ -58,6 +58,7 @@
 set(CMAKE_C_EXTENSIONS OFF)     # Force the usage of _ISOC11_SOURCE
 set(CMAKE_SYSTEM_LIBRARY_PATH "${RISCV_TOOLCHAIN_ROOT}/riscv32-unknown-elf/lib")
 set(RISCV_COMPILER_FLAGS "${RISCV_COMPILER_FLAGS} -march=rv32im -mabi=ilp32")
+set(RISCV_COMPILER_FLAGS "${RISCV_COMPILER_FLAGS} -DIREE_TIME_NOW_FN=\"\{ return 0; \}\"")
 
 add_compile_definitions(IREE_PLATFORM_GENERIC)