raise kernel load addr and slip stack under kernel on both 32bit and 64bit

[cleverca22]

while using circuitpython on a pi-zero, i discovered that the stack code code was broken
32bit was operating in dynamic stack mode, but reporting entirely wrong addresses for things
but i noticed, aarch64 on the broadcom port, puts the stack below the kernel load addr

so i just used kernel_address=0x100000 to change the load addr, for both 32bit and 64bit, raising it up a bit more
and made both 32bit and 64bit both have the stack below the kernel, allowing for the code to be simpler

edit:
confirmed the raspberrypi_zero_w build works on a zero-w
the raspberrypi_zero_w build also partially works on a pi1b, but the usb-hub blocks usb-device mode

the raspberrypi_zero2w build works on the zero2w
but hangs mid-boot on a pi3b (same SoC, but with a usb hub)

the raspberrypi_pi4b build boots on a pi4, but no usb-device or hdmi
repl works in hw uart

[RetiredWizard]

I've tested this on both a Zero W and a Zero 2W and it looks like it fixes #8044 for the Zero. The Zero 2W still has issues with USB activity causing hangs but if you use a terminal over the RX/TX pins, the Zero 2W has been relatively stable. During my testing I didn't see any negative impact from this PR on either Zero or the Zero 2W.

[tannewt]

I think you've updated the broadcom-peripherals library on your fork. Please PR those changes to the adafruit version first and then point this PR to it. (Sorry it is annoying.) IIRC tinyusb also uses the peripheral library for its testing.

[tannewt]

I think you want to point to adafruit/broadcom-peripherals@ec10438 since it is derived from the merge commit. (That repo is a little weird.)

[cleverca22]

that might explain why i had an extra 40 commits in my original pr
edit:
oh, and why broadcom/gen/bcm2835_lpa.h is now missing

[tannewt]

Thanks for the fix!