arm64: xilinx: Fix opp-table-cpu

OPP table name now should start with "opp-table" and OPP entries
shouldn't contain commas and @ signs in accordance to the new schema
requirement.

The same change was done by commit c6d4a897 ("ARM: tegra: Rename CPU
and EMC OPP table device-tree nodes"), commit ffbe853a ("ARM: dts:
sunxi: Fix OPPs node name") or commit b7072cc5 ("arm64: dts: qcom:
qcs404: Rename CPU and CPR OPP tables").

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/3297772b58953e4afd91f7a4bd845713e36e1e27.1652713489.git.michal.simek@amd.com