Fix build for mips.XLP64 kernel, by re-ordering headers.

[rpokala]

Summary

The log for the failure contained errors like this:

In file included from ${SRCTOP}/sys/mips/nlm/dev/net/xlpge.c:34:
In file included from ${SRCTOP}/sys/sys/systm.h:44:
In file included from ./machine/atomic.h:849:
${SRCTOP}/sys/sys/_atomic_subword.h:222:37: error: unknown type name 'u_long'; did you mean 'long'?
atomic_testandset_acq_long(volatile u_long *p, u_int v)
                                    ^~~~~~
                                    long

And similar "unknown type name" errors for u_int, not recognizing bool as a type, etc.

This was caused by including <sys/param.h> too far down; move it up where it belongs.

Test Plan

make tinderbox -DMAKE_JUST_KERNELS

[emaste]

do you know when this broke?

sys/mips/nlm/dev/net/xlpge.c

33

from style(9), <sys/types.h> includes <sys/cdefs.h>, and it is okay to depend on that

[jhb]

sys/mips/nlm/dev/net/xlpge.c

37

This is the real bug. <sys/param.h> needs to be moved first before <sys/endian.h>

[jhb]

I would also add a blank line after the "$FreeBSD$" since that seems to be the typical style.

sys/cdefs.h is needed for __FBSDID, so that should stay.

[rpokala]

Address review comments from emaste and jhb:

<sys/cdefs.h> includes <sys/types.h>, so it is not necessary to include it
here. The real issue is that <sys/param.h> needs to be included before
<sys/endian.h>.

Also, add a blank line after __FBSDID().

[emaste]

OK