MAINTAINERS: Remove myself (for raspi).

Signed-off-by: Andrew Baumann <Andrew.Baumann@microsoft.com>
Message-id: MW4PR21MB1940E8BB52F4053C943B1FCD9E219@MW4PR21MB1940.namprd21.prod.outlook.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

MAINTAINERS

@@ -818,7 +818,6 @@ F: docs/system/arm/palm.rst
 
 Raspberry Pi
 M: Peter Maydell <peter.maydell@linaro.org>
-R: Andrew Baumann <Andrew.Baumann@microsoft.com>
 R: Philippe Mathieu-Daudé <f4bug@amsat.org>
 L: qemu-arm@nongnu.org
 S: Odd Fixes