intel: Share code to read render timestamp

Timestamp read is not in any hot path so there is no down-sides in
share the same function between iris, crocus, anv and hasvk.

Also while at it also dropping the functions to read MMIO from kernel,
the only use is read render timestamp so we don't need it.

v2:
- fix compilaton of ds

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18920>

src/intel/vulkan/anv_gem.c

@@ -385,19 +385,6 @@ anv_gem_fd_to_handle(struct anv_device *device, int fd)
    return args.handle;
 }
 
-int
-anv_gem_reg_read(int fd, uint32_t offset, uint64_t *result)
-{
-   struct drm_i915_reg_read args = {
-      .offset = offset
-   };
-
-   int ret = intel_ioctl(fd, DRM_IOCTL_I915_REG_READ, &args);
-
-   *result = args.val;
-   return ret;
-}
-
 struct drm_i915_query_engine_info *
 anv_gem_get_engine_info(int fd)
 {