clk: rmobile: Split R8A7795 and R8A7796 core clock tables

The R8A7795 and R8A7796 tables use different constants to identify
clock in DT, so split the tables and use the correct constants on
R8A7795. This fixes UART clock misconfiguration on R8A7795.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>