clk: scmi: Add Kconfig option for SPL

Building U-Boot SPL with CLK_SCMI and SCMI_FIRMWARE Kconfig options
enabled and SPL_FIRMWARE disabled result in the following error.

  drivers/clk/clk_scmi.o: in function `scmi_clk_gate':
  drivers/clk/clk_scmi.c:84: undefined reference to `devm_scmi_process_msg'
  drivers/clk/clk_scmi.c:88: undefined reference to `scmi_to_linux_errno'
  drivers/clk/clk_scmi.o: in function `scmi_clk_get_rate':
  drivers/clk/clk_scmi.c:113: undefined reference to `devm_scmi_process_msg'
  drivers/clk/clk_scmi.c:117: undefined reference to `scmi_to_linux_errno'
  drivers/clk/clk_scmi.o: in function `scmi_clk_set_rate':
  drivers/clk/clk_scmi.c:139: undefined reference to `devm_scmi_process_msg'
  drivers/clk/clk_scmi.c:143: undefined reference to `scmi_to_linux_errno'
  drivers/clk/clk_scmi.o: in function `scmi_clk_probe':
  drivers/clk/clk_scmi.c:157: undefined reference to `devm_scmi_of_get_channel'
  make[1]: *** [scripts/Makefile.spl:527: spl/u-boot-spl] Error 1
  make: *** [Makefile:2043: spl/u-boot-spl] Error 2

Add Kconfig option so that CLK_SCMI can be disabled in SPL to fix this.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index c274cda..c134777 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -39,7 +39,7 @@
 obj-$(CONFIG_CLK_OCTEON) += clk_octeon.o
 obj-$(CONFIG_CLK_OWL) += owl/
 obj-$(CONFIG_CLK_RENESAS) += renesas/
-obj-$(CONFIG_CLK_SCMI) += clk_scmi.o
+obj-$(CONFIG_$(SPL_TPL_)CLK_SCMI) += clk_scmi.o
 obj-$(CONFIG_CLK_SIFIVE) += sifive/
 obj-$(CONFIG_CLK_UNIPHIER) += uniphier/
 obj-$(CONFIG_CLK_VERSACLOCK) += clk_versaclock.o