altos/stm: arm-none-eabi-binutils now puts 'main' into .text.startup

Change name of .text.ram to .ramtext, then load .text* into flash and
.ramtext into ram. This ensures that 'main' and anything else in a
random .text.* segment will get loaded into flash as appropriate.

Signed-off-by: Keith Packard <keithp@keithp.com>