dt-bindings: clock: ehrpwm: Add AM62 specific compatible

dt-bindings: clock: ehrpwm: Add AM62 specific compatible

Introduce AM62 specific compatible for EPWM time-base
sub-module clock. The time-base clock setup is identical
to AM64. The only difference is AM62 provides 3 time-base
clocks instead of the 9 found in AM64.

Signed-off-by: Georgi Vlaev <g-vlaev@ti.com>
Tested-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20220415190343.6284-2-g-vlaev@ti.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>