Rename e{malloc,realloc,free} to u{malloc,realloc,free}, to more obviously

reflect the fact that they allocate and deallocate user memory (i.e.
things reached through a userptr_t).

src/include/gpxe/umalloc.h

@@ -0,0 +1,17 @@
+#ifndef _GPXE_UMALLOC_H
+#define _GPXE_UMALLOC_H
+
+/**
+ * @file
+ *
+ * User memory allocation
+ *
+ */
+
+#include <gpxe/uaccess.h>
+
+extern userptr_t umalloc ( size_t size );
+extern userptr_t urealloc ( userptr_t ptr, size_t new_size );
+extern void ufree ( userptr_t ptr );
+
+#endif /* _GPXE_UMALLOC_H */