mach-k3: common_fdt: Move carveout struct

mach-k3: common_fdt: Move carveout struct

Labels are not allowed before declarations. Move the carveout struct
at the beginning and only update 'end' at this point.

This will fix following error:

arch/arm/mach-k3/common_fdt.c: In function 'fdt_fixup_reserved':
arch/arm/mach-k3/common_fdt.c:156:2: error: a label can only be part of a statement and a declaration is not a statement
  156 |  struct fdt_memory carveout = {
      |  ^~~~~~
make[1]: *** [scripts/Makefile.build:256: arch/arm/mach-k3/common_fdt.o] Error 1
make: *** [Makefile:1919: arch/arm/mach-k3] Error 2

Fixes: 096aa229a9e ("mach-k3: common_fdt: create a reserved memory node")

Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
Reviewed-by: Udit Kumar <u-kumar1@ti.com>
Reviewed-by: Bryan Brattlof <bb@ti.com>