ARM: UniPhier: remove SSC_WAY_SIZE and SSC_NUM_ENTRIES macros

Each way of the system cache has 256 entries for PH1-Pro4 and older
SoCs, whereas 512 entries for PH1-Pro5 and newer SoCs.  The line
size is still 128 byte.  Thus, the way size is 32KB/64KB for old/new
SoCs.

To keep lowlevel_init SoC-independent, set BOOT_RAM_SIZE to the
constant value 32KB.  It is large enough for temporary RAM and
should work for all the SoCs of UniPhier family.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>