x86/kexec: add -fno-PIE

[ Upstream commit 90944e40ba1838de4b2a9290cf273f9d76bd3bdd ]

If the gcc is configured to do -fPIE by default then the build aborts
later with:
| Unsupported relocation type: unknown type rel type name (29)

Tagging it stable so it is possible to compile recent stable kernels as
well.

Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Michal Marek <mmarek@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>