Add support for loader.efi on arm64

[andrew]

Summary

This adds loader.efi and boot1.efi for arm64.

[emaste]

sys/boot/efi/loader/arch/arm64/Makefile.inc

10

I wonder if we should just put cache.c in the arch/arm64 subdir, unless we expect libarm64 to grow over time and find non-EFI boot consumers

sys/boot/efi/loader/copy.c

64–71

Can we also expand this comment a bit explaining why we have to round up on arm and arm64?

[emaste]

Whitespace complaints from git:

<stdin>:170: trailing whitespace.
.elif ${MACHINE_CPUARCH} == "aarch64" 
<stdin>:278: trailing whitespace.
    // No ANSI C 1999/2000 stdint.h integer width declarations 
<stdin>:282: trailing whitespace.
        // Use Microsoft C compiler integer width declarations 
<stdin>:292: trailing whitespace.
    #else             
<stdin>:295: trailing whitespace.
            // Use LP64 programming model from C_FLAGS for integer width declarations 
warning: squelched 14 whitespace errors
warning: 19 lines add whitespace errors.

sys/boot/common/Makefile.inc

12

trailing whitespace

[andrew]

Update based on comments

[andrew]

https://svnweb.freebsd.org/changeset/base/281526

sys/boot/efi/loader/arch/arm64/Makefile.inc

10

I expect we may gain U-Boot support for embedded devices. Some of the code for this would live in sys/boot/arm64/uboot.