net: dwc-xlgmac: fix missing MODULE_DESCRIPTION() warning

With ARCH=hexagon, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/net/ethernet/synopsys/dwc-xlgmac.o

With most other ARCH settings the MODULE_DESCRIPTION() is provided by
the macro invocation in dwc-xlgmac-pci.c. However, for hexagon, the
PCI bus is not enabled, and hence CONFIG_DWC_XLGMAC_PCI is not set.
As a result, dwc-xlgmac-pci.c is not compiled, and hence is not linked
into dwc-xlgmac.o.

To avoid this issue, relocate the MODULE_DESCRIPTION() and other
related macros from dwc-xlgmac-pci.c to dwc-xlgmac-common.c, since
that file already has an existing MODULE_LICENSE() and it is
unconditionally linked into dwc-xlgmac.o.

Signed-off-by: Jeff Johnson <[e-mail]>
Link: https://lore.kernel.org/r/202[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/synopsys/dwc-xlgmac-common.c

···
 #include "dwc-xlgmac.h"
 #include "dwc-xlgmac-reg.h"
 
-MODULE_LICENSE("Dual BSD/GPL");
-
 static int debug = -1;
 module_param(debug, int, 0644);
 MODULE_PARM_DESC(debug, "DWC ethernet debug level (0=none,...,16=all)");
···
 	XLGMAC_PR("=====================================================\n");
 	XLGMAC_PR("\n");
 }
+
+MODULE_DESCRIPTION(XLGMAC_DRV_DESC);
+MODULE_VERSION(XLGMAC_DRV_VERSION);
+MODULE_AUTHOR("Jie Deng <[e-mail]>");
+MODULE_LICENSE("Dual BSD/GPL");

drivers/net/ethernet/synopsys/dwc-xlgmac-pci.c

···
 };
 
 module_pci_driver(xlgmac_pci_driver);
-
-MODULE_DESCRIPTION(XLGMAC_DRV_DESC);
-MODULE_VERSION(XLGMAC_DRV_VERSION);
-MODULE_AUTHOR("Jie Deng <[e-mail]>");
-MODULE_LICENSE("Dual BSD/GPL");