fix(core): use stm32f4 implementation of secret.c for unix too

(fixes bootloader_emu build because there was an error in the unix dummy
impl)

core/embed/trezorhal/unix/secret.c

@@ -1,9 +0,0 @@
-#include "secret.h"
-
-void secret_write(uint8_t* data, uint32_t offset, uint32_t len) {}
-
-void secret_read(uint8_t* data, uint32_t offset, uint32_t len) {}
-
-secbool secret_wiped(void) { return secfalse; }
-
-void secret_erase(void) {}

core/embed/trezorhal/unix/secret.c

@@ -0,0 +1 @@
+../stm32f4/secret.c