Fixes the following w1 warning:

drivers/of/kexec.c:126:5: warning: no previous prototype for 'ima_get_kexec_buffer' [-Wmissing-prototypes]
drivers/of/kexec.c:153:5: warning: no previous prototype for 'ima_free_kexec_buffer' [-Wmissing-prototypes

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: sunliming <sunliming@kylinos.cn>
---
 include/linux/of.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/of.h b/include/linux/of.h
index f0a5d6b10c5a..3a166a1c4ef6 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -844,6 +844,16 @@ static inline phys_addr_t of_dma_get_max_cpu_address(struct device_node *np)
 	return PHYS_ADDR_MAX;
 }
 
+static inline int ima_get_kexec_buffer(void **addr, size_t *size)
+{
+        return -ENOSYS;
+}
+
+static inline int ima_free_kexec_buffer(void **addr, size_t *size)
+{
+        return -ENOSYS;
+}
+
 #define of_match_ptr(_ptr)	NULL
 #define of_match_node(_matches, _node)	NULL
 #endif /* CONFIG_OF */
-- 
2.25.1