init/main.c: include <linux/mem_encrypt.h>

init/main.c: include <linux/mem_encrypt.h>

In commit c7753208a94c ("x86, swiotlb: Add memory encryption support") a
call to function `mem_encrypt_init' was added.  Include prototype
defined in header <linux/mem_encrypt.h> to prevent a warning reported
during compilation with W=1:

  init/main.c:494:20: warning: no previous prototype for `mem_encrypt_init' [-Wmissing-prototypes]

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Mathieu Malaterre <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Acked-by: Steven Rostedt (VMware) <[email protected]>
Cc: Tom Lendacky <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Dominik Brodowski <[email protected]>
Cc: Gargi Sharma <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>