Add filesystem code and storage syscalls

Adds syscalls:

- ALLOCATE_AREA
- DEALLOCATE_AREA
- WRITE_DATA
- READ_DATA

and code to access the filesystem and the flash over SPI.

Based on original work by Daniel Jobson <jobson@tillitis.see> for
these files:

- auth_app.[ch]
- flash.[ch]
- spi.[ch]
- partition_table.[ch]
- rng.[ch]
- storage.[ch]

which are used with small changes to integrate with the new syscall
method.

Co-authored-by: Daniel Jobson <jobson@tillitis.se>
Co-authored-by: Mikael Ågren <mikael@tillitis.se>

hw/application_fpga/fw/tk1/main.c

@@ -12,6 +12,7 @@
 #include <tkey/tk1_mem.h>
 
 #include "blake2s/blake2s.h"
+#include "partition_table.h"
 #include "proto.h"
 #include "state.h"
 #include "syscall_enable.h"
@@ -35,6 +36,8 @@ static volatile uint32_t *ram_addr_rand    = (volatile uint32_t *)TK1_MMIO_TK1_R
 static volatile uint32_t *ram_data_rand    = (volatile uint32_t *)TK1_MMIO_TK1_RAM_DATA_RAND;
 // clang-format on
 
+struct partition_table part_table;
+
 // Context for the loading of a TKey program
 struct context {
 	uint32_t left;	    // Bytes left to receive
@@ -418,6 +421,11 @@ int main(void)
 
 	scramble_ram();
 
+	if (part_table_read(&part_table) != 0) {
+		// Couldn't read or create partition table
+		assert(1 == 2);
+	}
+
 #if defined(SIMULATION)
 	run(&ctx);
 #endif