zynqmp: pm: Reimplement clock get state (status) EEMI API

zynqmp: pm: Reimplement clock get state (status) EEMI API

Clock get state EEMI API is reimplemented to use system-level clock
and pll EEMI APIs rather than direct MMIO read/write accesses to clock
and pll control registers.
Since linux is_enabled method for PLLs still uses clock get state API
get the PLL state, in the implementation of pm_clock_getstate() we need
to workaround this by distinguishing two cases: 1) if the given clock ID
corresponds to a PLL output clock ID; or 2) given clock ID is truly an
on-chip clock whose state of the gate should be returned.
For case 1) we'll call pm_api_clock_pll_getstate() implemented in
pm_api_clock.h/c. This function will query the PLL state from PMU using
the system-level PLL get mode EEMI API.
For case 2) we'll call the PMU to query the clock gate state using
system-level clock get status EEMI API.
Functions that appear to be unused after this change is made are removed.

Signed-off-by: Mirela Simonovic <mirela.simonovic@aggios.com>
Acked-by: Will Wong <WILLW@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>