hw/xtensa/xtfpga: fix FLASH mapping to boot region for KC705

On KC705 bootloader area is located at FLASH offset 0x06000000, not 0 as
on older xtfpga boards.

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa: remove extraneous xtensa_ prefix from file names

While at it rename lx60 (named after the first board of the family) to
more generic xtfpga (the family name).

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa: replace fprintfs with error_report

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa/xtfpga: retrieve parameters from machine_opts

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa/xtfpga: use symbolic constants for bootparam tags

Import bootparam tag names from linux/arch/xtensa/include/asm/bootparam.h
No functional changes.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa/xtfpga: refactor bootparameters filling

Separate filling first/last tag and size calculation from the kernel
command line setup.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa/xtfpga: add memory info to bootparam

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa/xtfpga: implement uImage loading

Provide a simple bootloader code at the reset address that jumps to the
loaded image entry point when it's not equal to the reset address. This
is needed because the old method of setting pc doesn't work due to cpu
reset done after the machine setup.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa/xtfpga: implement DTB loading

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
hw/xtensa/xtfpga: implement initrd loading

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