microblaze: drop CONFIG_SYS_RESET_ADDRESS macro

microblaze: drop CONFIG_SYS_RESET_ADDRESS macro

Microblaze is one the last two users of the CONFIG_SYS_RESET_ADDRESS
macro (the other is arch/powerpc/cpu/mpc8xx/cpu.c, but the macro is not
defined anywhere in powerpc code, so it should be removed there too).

Replace CONFIG_SYS_RESET_ADDRESS usage in start.S with
CONFIG_SYS_TEXT_BASE. If the reset address should really be
user-configurable, a new Kconfig option could be added.

Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Link: https://lore.kernel.org/r/20211130163358.2531677-6-ovidiu.panait@windriver.com
Signed-off-by: Michal Simek <michal.simek@xilinx.com>