clk: sifive: Add clock driver for GEMGXL MGMT

This adds a clock driver to support the GEMGXL management IP block
found in FU540 SoCs to control GEM TX clock operation mode for
10/100/1000 Mbps.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Tested-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
diff --git a/drivers/clk/sifive/Makefile b/drivers/clk/sifive/Makefile
index 1155e07..f8263e7 100644
--- a/drivers/clk/sifive/Makefile
+++ b/drivers/clk/sifive/Makefile
@@ -3,3 +3,5 @@
 obj-$(CONFIG_CLK_ANALOGBITS_WRPLL_CLN28HPC)	+= wrpll-cln28hpc.o
 
 obj-$(CONFIG_CLK_SIFIVE_FU540_PRCI)		+= fu540-prci.o
+
+obj-$(CONFIG_CLK_SIFIVE_GEMGXL_MGMT)		+= gemgxl-mgmt.o