nrf/mpconfigport: Enable MICROPY_PY_MACHINE_BOOTLOADER.

This should have been enabled in 48b5a7b0
but was missed.
Signed-off-by: Damien George <damien@micropython.org>

ports/nrf/mpconfigport.h

@@ -175,6 +175,7 @@
 #define MICROPY_PY_MACHINE          (1)
 #define MICROPY_PY_MACHINE_INCLUDEFILE "ports/nrf/modules/machine/modmachine.c"
 #define MICROPY_PY_MACHINE_BARE_METAL_FUNCS (1)
+#define MICROPY_PY_MACHINE_BOOTLOADER (1)
 #define MICROPY_PY_MACHINE_PULSE    (0)
 #define MICROPY_PY_MACHINE_SOFTI2C  (MICROPY_PY_MACHINE_I2C)