clk: stm32mp1: Add parent_data to ETHRX clock

clk: stm32mp1: Add parent_data to ETHRX clock

Pass parent_data to ETHRX clock with new fw_name = "ETH_RX_CLK/ETH_REF_CLK".
By default, this change has no impact on the operation of the clock driver.
However, due to the fw_name, it permits DT to override ETHRX clock parent,
which might be needed in case the ETHRX clock are supplied by external clock
source.

Example of MCO2 supplying clock to ETH_RX_CLK via external pad-to-pad wire:
&rcc {
         clocks = <&rcc CK_MCO2>;
         clock-names = "ETH_RX_CLK/ETH_REF_CLK";
};

Note that while this patch permits to implement this rare usecase, the issue
with ethernet RX and TX input clock modeling on MP1 is far more complex and
requires more core plumbing.

[1] STM32MP1 Reference Manual RM0436 Rev 3, Page 574,
    Figure 83. Peripheral clock distribution for Ethernet
    https://www.st.com/resource/en/reference_manual/dm00327659-stm32mp157-advanced-armbased-32bit-mpus-stmicroelectronics.pdf

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Christophe Roullier <christophe.roullier@foss.st.com>
Cc: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc: linux-clk@vger.kernel.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Link: https://lore.kernel.org/r/20220118202958.1840431-2-marex@denx.de
Tested-by: Johann Neuhauser <jneuhauser@dh-electronics.com>
Acked-by: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>