iommu/vt-d: Convert non-returned local variable to boolean when relevant

This patch was produced using Coccinelle. A simplified version of the
semantic patch is:

@r exists@
identifier f;
local idexpression u8 x;
identifier xname;
@@

f(...) {
...when any
(
  x@xname = 1;
|
  x@xname = 0;
)
...when any
}

@bad exists@
identifier r.f;
local idexpression u8 r.x
expression e1 != {0, 1}, e2;
@@

f(...) {
...when any
(
  x = e1;
|
  x + e2
)
...when any
}

@depends on !bad@
identifier r.f;
local idexpression u8 r.x;
identifier r.xname;
@@

f(...) {
...
++ bool xname;
- int xname;
<...
(
  x =
- 1
+ true
|
  x =
- -1
+ false
)
...>

}

Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>