fastbootd: reset file descriptor on unaligned writes

Writes on file descriptors opened with O_DIRECT will fail if the buffer
is not page aligned. This CL will reset the file descriptor without the
O_DIRECT flag for such instances.

Bug: 225108941
Signed-off-by: Konstantin Vyshetsky <vkon@google.com>
Change-Id: I841c84f5d2c0b9435b394c48b1bfcc2d51d771bb