MFC r316080,r316081,r316115:

MFC r316080,r316081,r316115:

r316080:

Fix some localized style(9) issues and reword CAM_ERRBUF_SIZE description

The CAM_ERRBUF_SIZE description rewording fixes a typo by proxy.

r316081:

Use `sizeof(cam_errbuf)` instead of `CAM_ERRBUF_SIZE` in snprintf calls

Reindent snprintf calls' arguments to match style(9) guidelines with
respect to indentation.

r316115:

libcam: use __func__ instead of hardcoding the function name as `func_name`

Tested with:	`cam_device_copy(NULL, NULL)` // ;)..

git-svn-id: svn://svn.freebsd.org/base/stable/10@316316 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f