arm64: dts: renesas: r8a774a1: Add CPU capacity-dmips-mhz

arm64: dts: renesas: r8a774a1: Add CPU capacity-dmips-mhz

Set the capacity-dmips-mhz for RZ/G2M(r8a774a1) SoC, that is based on
dhrystone.

Based on work done by Gaku Inami <gaku.inami.xw@bp.renesas.com> for
r8a7796 SoC.

The average dhrystone result for 5 iterations is as below:

r8a774a1 SoC (CA57x2 + CA53x4)
  CPU   max-freq   dhrystone
  ---------------------------------
  CA57   1500 MHz  11428571 lps/s
  CA53   1200 MHz   5000000 lps/s

From this, CPU capacity-dmips-mhz for CA57 and CA53 are calculated
as follows:

r8a774a1 SoC
  CA57 : 1024 / (11428571 / 1500) * (11428571 / 1500) = 1024
  CA53 : 1024 / (11428571 / 1500) * ( 5000000 / 1200) =  560

Since each CPUs have different max frequencies, the final CPU
capacities of A53 scaled by the above difference is as below

$ cat /sys/devices/system/cpu/cpu*/cpu_capacity
1024
1024
448
448
448
448

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>