fsp_srv: Log out option values in IFile's Read and Write functions

These indicate options that alter how a read/write is performed.

Currently we don't need to handle these, as the only one that seems to
be used is for writes, but all the custom options ever seem to do is
immediate flushing, which we already do by default.

src/core/hle/service/filesystem/fsp_srv.cpp

@@ -115,11 +115,12 @@ private:
 
     void Read(Kernel::HLERequestContext& ctx) {
         IPC::RequestParser rp{ctx};
-        const u64 unk = rp.Pop<u64>();
+        const u64 option = rp.Pop<u64>();
         const s64 offset = rp.Pop<s64>();
         const s64 length = rp.Pop<s64>();
 
-        LOG_DEBUG(Service_FS, "called, offset=0x{:X}, length={}", offset, length);
+        LOG_DEBUG(Service_FS, "called, option={}, offset=0x{:X}, length={}", option, offset,
+                  length);
 
         // Error checking
         if (length < 0) {
@@ -148,11 +149,12 @@ private:
 
     void Write(Kernel::HLERequestContext& ctx) {
         IPC::RequestParser rp{ctx};
-        const u64 unk = rp.Pop<u64>();
+        const u64 option = rp.Pop<u64>();
         const s64 offset = rp.Pop<s64>();
         const s64 length = rp.Pop<s64>();
 
-        LOG_DEBUG(Service_FS, "called, offset=0x{:X}, length={}", offset, length);
+        LOG_DEBUG(Service_FS, "called, option={}, offset=0x{:X}, length={}", option, offset,
+                  length);
 
         // Error checking
         if (length < 0) {