soc: renesas: rz-sysc: #undef field_get() before local definition

Prepare for the advent of a globally available common field_get() macro
by undefining the symbol before defining a local variant.  This prevents
redefinition warnings from the C preprocessor when introducing the common
macro later.

Suggested-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>

Author: geertu

drivers/soc/renesas/rz-sysc.c

@@ -16,6 +16,7 @@
 
 #include "rz-sysc.h"
 
+#undef field_get
 #define field_get(_mask, _reg) (((_reg) & (_mask)) >> (ffs(_mask) - 1))
 
 /**