remoteproc: k3-dsp: Fix unbalanced state machine in k3_dsp_start

The global module reset is deasserted through the ti_sci_power_domain_on()
call in k3_dsp_start(), but is not asserted back if the local module reset
fails. Fix this.

While at this, remove the stale comment about assigned-clock-rates that
seems to have been copied from the K3 ARM64 Remoteproc driver.

Fixes: ab827b38 ("remoteproc: Introduce K3 C66 and C71 remoteproc driver")
Signed-off-by: Suman Anna <s-anna@ti.com>