Convert hello_interp.c:times_table to µPython

Not useful for efficient calculation of times-tables (it is not) but a nice
way to show accessing hardware registers in the rp2040 from µPython

interp/interp.py

@@ -0,0 +1,12 @@
+from machine import mem32
+
+# initialise lane 0 on interp: set that we are using all 32 bits
+mem32[0xD0000000 | 0xAC] = 0x1F << 10
+
+# set up 9 x table example - write to accum[0] and base[0] registers
+mem32[0xD0000000 | 0x80] = 0
+mem32[0xD0000000 | 0x88] = 9
+
+# read pop register 10 times
+for j in range(10):
+    print(mem32[0xD0000000 | 0x94])