phy: ralink: phy-mt7621-pci: drop 'COMPILE_TEST' from Kconfig

This driver includes the following two files directly:
- mt7621.h
- ralink_regs.h

Compilation for its related platform properly works because
its real path is included in 'arch/mips/ralink/Platform' as
cflags.

This driver depends on RALINK but also is enabled for COMPILE_TEST
where nothing about its platform is known and this directly
included files are not found at all breaking compilation.

If we want 'COMPILE_TEST' we have to change cflags also inside
'phy/ralink' subdirectory Makefile which seems that does not
like to linux-phy maintainers. Hence remove COMPILE_TEST from
Kconfig to avoid the problem.

Fixes: d87da32372a0 ("phy: ralink: Add PHY driver for MT7621 PCIe PHY")
Reported-by: Stephen Rothwell <[e-mail]>
Signed-off-by: Sergio Paracuellos <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/phy/ralink/Kconfig

···
 #
 config PHY_MT7621_PCI
 	tristate "MediaTek MT7621 PCI PHY Driver"
-	depends on (RALINK || COMPILE_TEST) && OF
+	depends on RALINK && OF
 	select GENERIC_PHY
 	select REGMAP_MMIO
 	help