printk: Fix alignment of buf causing crash on ARM EABI
printk: Fix alignment of buf causing crash on ARM EABI

Commit 7ff9554bb578ba02166071d2d487b7fc7d860d62, printk: convert
byte-buffer to variable-length record buffer, causes systems using
EABI to crash very early in the boot cycle. The first entry in struct
log is a u64, which for EABI must be 8 byte aligned.

Make use of __alignof__() so the compiler to decide the alignment, but
allow it to be overridden using CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
for systems which can perform unaligned access and want to save
a few bytes of space.

Tested on Orion5x and Kirkwood.

Signed-off-by: Andrew Lunn <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@lunn.ch>
Tested-by: Stephen Warren <5ef2a23ba3aff51d1cfc8c113c1ec34b608b3b13@wwwdotorg.org>
Acked-by: Stephen Warren <5ef2a23ba3aff51d1cfc8c113c1ec34b608b3b13@wwwdotorg.org>
Acked-by: Kay Sievers <e9264147b413746293e539868c8edff71715e1e3@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas