vfio: Don't exit at get_region_info failure
vfio: Don't exit at get_region_info failure

At vfio device initialization, it will probe all the defined regions,
most device don't have vga region, then when crosvm probe vga region info,
kernel vfio will return -EINVAL. So when error happens, it should continue
getting the next region info, instead of exit.

BUG=None
TEST=passthrough non graphic device into guest

Change-Id: If4d2f723df45f58ccd733e03c854cdcef3530bdb
Signed-off-by: Xiong Zhang <887154684953c1d7bc9f653d05b20c8de98c15bc@intel.corp-partner.google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1918486
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

google/crosvm,google/crosvm,google/crosvm,google/crosvm