crypto internal: Make MD4 PADDING array const

The PADDING array used when adding padding bits in MD4 never change
so can be made const. Making it const puts the array in .rodata
section and can save a few bytes of RAM for systems running without
virtual memory.

Signed-off-by: Mikael Kanstrup <mikael.kanstrup@sony.com>

src/crypto/md4-internal.c

@@ -85,7 +85,7 @@ MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH]);
 	(cp)[1] = (value) >> 8;						\
 	(cp)[0] = (value); } while (0)
 
-static u8 PADDING[MD4_BLOCK_LENGTH] = {
+static const u8 PADDING[MD4_BLOCK_LENGTH] = {
 	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0