MAINTAINERS: fix bad sdei paths

The SDEI header files had an 'arm_' namespace added, but the patterns
in the MAINTAINERS files were missed. Oops.
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

MAINTAINERS

@@ -13480,8 +13480,8 @@ L:	linux-arm-kernel@lists.infradead.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/arm/firmware/sdei.txt
 F:	drivers/firmware/arm_sdei.c
-F:	include/linux/sdei.h
-F:	include/uapi/linux/sdei.h
+F:	include/linux/arm_sdei.h
+F:	include/uapi/linux/arm_sdei.h
 
 SOFTWARE RAID (Multiple Disks) SUPPORT
 M:	Shaohua Li <shli@kernel.org>