SUBSYSTEMS.md: add @maribu

Author: maribu

SUBSYSTEMS.md

@@ -14,8 +14,12 @@ affect more than one module.
 
 ## MSP430
 
+- Marian Buschsieweke (@maribu)
+
 ## ARM7
 
+- Marian Buschsieweke (@maribu)
+
 ## ARM Cortex-M
 
 ### Atmel Sam0 line (SAM D1x/D2x, L1x, L2x, D5x)
@@ -25,6 +29,8 @@ affect more than one module.
 
 ## Atmel AVR (Atmega)
 
+- Marian Buschsieweke (@maribu)
+
 ## Native
 
 ### ZEP radio simulation & ZEP dispatcher
@@ -70,10 +76,14 @@ affect more than one module.
 
 ### CC110X
 
+- Marian Buschsieweke (@maribu)
+
 ### ESP-NOW
 
 ## Peripherals
 
+- Marian Buschsieweke (@maribu)
+
 ## Other drivers
 
 # Kernel (core)
@@ -109,6 +119,8 @@ affect more than one module.
 
 ## C++ support
 
+- Marian Buschsieweke (@maribu)
+
 ## Crypto
 
 # Networking