pcmcia: db1xxx_ss: Mark expected switch fall-throughs

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings (Building: db1xxx_defconfig mips):

drivers/pcmcia/db1xxx_ss.c:257:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/pcmcia/db1xxx_ss.c:269:3: warning: this statement may fall through [-Wimplicit-fallthrough=]

Reviewed-by: Kees Cook <[e-mail]>
Signed-off-by: Gustavo A. R. Silva <[e-mail]>

drivers/pcmcia/db1xxx_ss.c

···
 	switch (state->Vcc) {
 	case 50:
 		++v;
+		/* fall through */
 	case 33:
 		++v;
+		/* fall through */
 	case 0:
 		break;
 	default:
···
 	switch (state->Vpp) {
 	case 12:
 		++p;
+		/* fall through */
 	case 33:
 	case 50:
 		++p;
+		/* fall through */
 	case 0:
 		break;
 	default: