CPER: Remove unnecessary use of user-space types

"__u32" and similar types are intended for things exported to user-space,
including structs used in ioctls; see include/uapi/asm-generic/int-l64.h.

They are not needed for the CPER struct definitions, which not exported to
user-space and not used in ioctls.  Replace them with the typical "u32" and
similar types.  No functional change intended.

The reason for changing this is to remove the question of "why do we use
__u32 here instead of u32?"  We should use __u32 when there's a reason for
it; otherwise, we should prefer u32 for consistency.

Reference: Documentation/process/coding-style.rst
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Masahiro Yamada <yamada.masahiro@socionext.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>