cfi: Include uaccess.h for get_kernel_nofault()

cfi: Include uaccess.h for get_kernel_nofault()

After commit 0652a3daa787 ("tracing: Fix CFI violation in probestub
being called by tprobes"), there are many build errors when building
ARCH=arm multi_v7_defconfig + CONFIG_CFI=y like:

  In file included from drivers/base/devres.c:17:
  In file included from drivers/base/trace.h:16:
  In file included from include/linux/tracepoint.h:23:
  include/linux/cfi.h:44:6: error: call to undeclared function 'get_kernel_nofault'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     44 |         if (get_kernel_nofault(hash, func - cfi_get_offset()))
        |             ^
  1 error generated.

get_kernel_nofault() is called in the generic version of
cfi_get_func_hash() but nothing ensures uaccess.h is always included for
a proper expansion and prototype.  Include uaccess.h in cfi.h to clear
up the errors.

Cc: stable@vger.kernel.org
Fixes: 0652a3daa787 ("tracing: Fix CFI violation in probestub being called by tprobes")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>