stand: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

gptboot.efi: align secbuf to 4K

The u-boot EFI implementation of the ReadBlocks and WriteBlocks methods
requires that the provided buffer meet the IO alignment requirements of
the underlying disk. Unlike loader.efi, gptboot.efi doesn't check this
requirement, and therefore fails to perform a successful read. Adjust
secbuf's alignment to 4K in hopes that we will always meet this
requirement.

Reviewed by: imp
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D25111

loader.efi: replace HandleProtocol() with OpenProtocol()

The HandleProtocol() is deprecated interface and we should use OpenProtocol()
instead. Moreover, in some firmware implementation(s), the HandleProtocol()
does return device path using static storage, so we can not keep the value
returned there. With same firmware, the OpenProtocol() does return data we
do not need to clone.

Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D21162

Create gptboot.efi

This is a primary boot loader that is intended to implement the
gptboot partition selection algorithm just like we did for BIOS
booting. While the preferred method for UEFI is to use the UEFI Boot
Manager protocol, there are situations where that can't be done: some
BIOS makers interfere with the protocol in unhelpful ways, there's a
new standard for a zero variable write from the client OS, and finally
for USB drives that might be mobile between systems with multiple
partitions there needs to be a media stable way to select.

Reviewed by: tsoome, bcran
Differential Revision: https://reviews.freebsd.org/D20547