board: dragonboard410c: Fix PHYS_SDRAM_1_SIZE

board: dragonboard410c: Fix PHYS_SDRAM_1_SIZE

The DragonBoard 410c has proprietary firmware from Qualcomm that
reserves 8 MiB of memory for tz/smem/hyp/rmtfs/rfsa from 0x86000000
to 0x86800000. I'm not aware of any ATF (ARM Trusted Firmware) port
for DB410c that would reserve 30 MiB of memory at the end of RAM.
I suspect the comment might have been copied from hikey.h which has
a very similar comment (and which actually does have an ATF port).

Reducing the memory size just prevents U-Boot from using the end of
the RAM, not the reserved region inbetween. Therefore we might as well
display the correct DRAM size (1 GiB) instead of strange 986 MiB.

Fixes: 626f048bbc14 ("board: Add Qualcomm Dragonboard 410C support")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>