xtensa: add missing XCHAL_HAVE_WINDOWED check

Add missing preprocessor conditions to secondary reset vector code.

Fixes: 09af39f649da ("xtensa: use register window specific opcodes only when present")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

xtensa: drop unused sections and remapped reset handlers

There are no .bootstrap or .ResetVector.text sections linked to the
vmlinux image, drop these sections from vmlinux.ld.S. Drop
RESET_VECTOR_VADDR definition only used for .ResetVector.text.

Drop remapped copies of primary and secondary reset vectors, as modern
gdb don't have problems stepping through instructions at arbitrary
locations. Drop corresponding sections from the corresponding linker
scripts.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

xtensa: add SMP support

This is largely based on SMP code from the xtensa-2.6.29-smp tree by
Piet Delaney, Marc Gauthier, Joe Taylor, Christian Zankel (and possibly
other Tensilica folks).

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>