add macros for number of adcs and dacs

firmware/generate_csr_locations.py

@@ -12,8 +12,11 @@ def get_reg(j, name, num, pos):
 
 j = json.load(open("csr.json"))
 
-print('''#pragma once
+print('''
+#pragma once
 typedef volatile uint32_t *csr_t;
+#define ADC_MAX 8
+#define DAC_MAX 8
 ''')
 
 for conv in iter(reg_names):