MAINTAINERS: fix DWMAC S32 entry

Using L: with more than a bare email address causes getmaintainer.pl
to be unable to parse the entry. Fix this by doing as other entries
that use this email address and convert it to an R: entry.

Link: https://patch.msgid.link/20250221005012.1051897-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

MAINTAINERS

@@ -2877,7 +2877,7 @@ F:	drivers/pinctrl/nxp/
 
 ARM/NXP S32G/S32R DWMAC ETHERNET DRIVER
 M:	Jan Petrous <jan.petrous@oss.nxp.com>
-L:	NXP S32 Linux Team <s32@nxp.com>
+R:	s32@nxp.com
 S:	Maintained
 F:	Documentation/devicetree/bindings/net/nxp,s32-dwmac.yaml
 F:	drivers/net/ethernet/stmicro/stmmac/dwmac-s32.c