net: ethernet: ti: Remove TI_CPTS_MOD workaround

net: ethernet: ti: Remove TI_CPTS_MOD workaround

My recent commit b6d49cab44b5 ("net: Make PTP-specific drivers depend on
PTP_1588_CLOCK") exposes a missing dependency in defconfigs that select
TI_CPTS without selecting PTP_1588_CLOCK, leading to linker errors of the
form:

drivers/net/ethernet/ti/cpsw.o: in function `cpsw_ndo_stop':
cpsw.c:(.text+0x680): undefined reference to `cpts_unregister'
 ...

That's because TI_CPTS_MOD (which is the symbol gating the _compilation_ of
cpts.c) now depends on PTP_1588_CLOCK, and so is not enabled in these
configurations, but TI_CPTS (which is the symbol gating _calls_ to the cpts
functions) _is_ enabled. So we end up compiling calls to functions that
don't exist, resulting in the linker errors.

This patch fixes build errors and restores previous behavior by:
 - ensure PTP_1588_CLOCK=y in TI specific configs and CPTS will be built
 - remove TI_CPTS_MOD and, instead, add dependencies from CPTS in
   TI_CPSW/TI_KEYSTONE_NETCP/TI_CPSW_SWITCHDEV as below:

   config TI_CPSW_SWITCHDEV
   ...
    depends on TI_CPTS || !TI_CPTS

   which will ensure proper dependencies PTP_1588_CLOCK -> TI_CPTS ->
TI_CPSW/TI_KEYSTONE_NETCP/TI_CPSW_SWITCHDEV and build type selection.

Note. For NFS boot + CPTS all of above configs have to be built-in.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Fixes: b6d49cab44b5 ("net: Make PTP-specific drivers depend on PTP_1588_CLOCK")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Clay McClure <clay@daemons.net>
[grygorii.strashko@ti.com: rewording, add deps cpsw/netcp from cpts, drop IS_REACHABLE]
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: David S. Miller <davem@davemloft.net>