libcamera: base: shared_fd: Rename fd() to get()

For consistency with UniqueFD, rename the fd() function to get().
Renaming UniqueFD::get() to fd() would have been another option, but was
rejected to keep as close as possible to the std::shared_ptr<> and
std::unique_ptr<> APIs.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>

src/cam/drm.cpp

@@ -608,12 +608,12 @@ std::unique_ptr<FrameBuffer> Device::createFrameBuffer(
 
 	unsigned int i = 0;
 	for (const libcamera::FrameBuffer::Plane &plane : planes) {
-		int fd = plane.fd.fd();
+		int fd = plane.fd.get();
 		uint32_t handle;
 
 		auto iter = fb->planes_.find(fd);
 		if (iter == fb->planes_.end()) {
-			ret = drmPrimeFDToHandle(fd_, plane.fd.fd(), &handle);
+			ret = drmPrimeFDToHandle(fd_, plane.fd.get(), &handle);
 			if (ret < 0) {
 				ret = -errno;
 				std::cerr