MAINTAINERS: remove Laszlo Ersek's entries

I've relinquished my edk2 roles with the following commit message [1] [2]
[3]:

> Maintainers.txt: remove Laszlo Ersek's entries
>
> I'm relinquishing all my roles listed in "Maintainers.txt", for personal
> reasons.
>
> My email address <[email protected]> remains functional.
>
> To my understanding, my employer is working to assign others engineers
> to the edk2 project (at their discretion).

[1] https://edk2.groups.io/g/devel/message/77585
[2] https://listman.redhat.com/archives/edk2-devel-archive/2021-July/msg00202.html
[3] http://mid.mail-archive.com/[email protected]

Accordingly, remove my entries from QEMU's MAINTAINERS file as well, which
all relate to guest firmware.

Cc: Daniel P. Berrange <[email protected]>
Cc: Gerd Hoffmann <[email protected]>
Cc: Kashyap Chamarthy <[email protected]>
Cc: Peter Maydell <[email protected]>
Cc: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Laszlo Ersek <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>

MAINTAINERS

@@ -2202,7 +2202,6 @@ F: include/hw/southbridge/piix.h
 
 Firmware configuration (fw_cfg)
 M: Philippe Mathieu-Daudé <[email protected]>
-R: Laszlo Ersek <[email protected]>
 R: Gerd Hoffmann <[email protected]>
 S: Supported
 F: docs/specs/fw_cfg.txt
@@ -2934,15 +2933,13 @@ F: include/hw/i2c/smbus_slave.h
 F: include/hw/i2c/smbus_eeprom.h
 
 Firmware schema specifications
-M: Laszlo Ersek <[email protected]>
 M: Philippe Mathieu-Daudé <[email protected]>
 R: Daniel P. Berrange <[email protected]>
 R: Kashyap Chamarthy <[email protected]>
 S: Maintained
 F: docs/interop/firmware.json
 
 EDK2 Firmware
-M: Laszlo Ersek <[email protected]>
 M: Philippe Mathieu-Daudé <[email protected]>
 S: Supported
 F: hw/i386/*ovmf*