Rely on updated newfs_msdos for parameter tuning.

The recently updated newfs_msdos tool has robust tuning logic
internally to pick balanced values for parameters like sectors-per-
cluster, so rely on it instead of trying to force invalid
configurations.

If stakeholders want to tune these parameters even further, they
should contribute to upstream newfs_msdos, where it will benefit
more than just Android devices.

Bug: 29899852
Test: manual with 512MB, 2GB and 34GB devices
Change-Id: I23ab3699f37fc428c2bd7dcbd84f825412d916e6
diff --git a/fs/Vfat.cpp b/fs/Vfat.cpp
index dc1fe33..57114b9 100644
--- a/fs/Vfat.cpp
+++ b/fs/Vfat.cpp
@@ -172,12 +172,8 @@
 status_t Format(const std::string& source, unsigned long numSectors) {
     std::vector<std::string> cmd;
     cmd.push_back(kMkfsPath);
-    cmd.push_back("-F");
-    cmd.push_back("32");
     cmd.push_back("-O");
     cmd.push_back("android");
-    cmd.push_back("-c");
-    cmd.push_back("64");
     cmd.push_back("-A");
 
     if (numSectors) {