intel/decoder: Fix is_header_field starting condition.

Starting positions >= 32 are not part of the header, rather than >.

Caught by Coverity, which found that "bits <<= field->start" may shift
by 32, which has undefined behavior.

CID: 1404968

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

src/intel/common/gen_decoder.c

@@ -849,7 +849,7 @@ is_header_field(struct gen_group *group, struct gen_field *field)
 {
    uint32_t bits;
 
-   if (field->start > 32)
+   if (field->start >= 32)
       return false;
 
    bits = (1U << (field->end - field->start + 1)) - 1;