powerpc: Use a macro for creating instructions from u32s

In preparation for instructions having a more complex data type start
using a macro, ppc_inst(), for making an instruction out of a u32.  A
macro is used so that instructions can be used as initializer elements.
Currently this does nothing, but it will allow for creating a data type
that can represent prefixed instructions.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Change include guard to _ASM_POWERPC_INST_H]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-7-jniethe5@gmail.com

arch/powerpc/kernel/crash_dump.c

@@ -18,6 +18,7 @@
 #include <asm/firmware.h>
 #include <linux/uaccess.h>
 #include <asm/rtas.h>
+#include <asm/inst.h>
 
 #ifdef DEBUG
 #include <asm/udbg.h>
@@ -44,7 +45,7 @@ static void __init create_trampoline(unsigned long addr)
 	 * branch to "addr" we jump to ("addr" + 32 MB). Although it requires
 	 * two instructions it doesn't require any registers.
 	 */
-	patch_instruction(p, PPC_INST_NOP);
+	patch_instruction(p, ppc_inst(PPC_INST_NOP));
 	patch_branch(++p, addr + PHYSICAL_START, 0);
 }