arm: Remove enforced Os flag for LZ4 decompressor
-Os is enforced here, based on the test result of decompression time below, slightly faster than -O2. But further tests with UA show that using -O2 will be the right choice especially in the case of the unaligned access enabled and the gap, few counts in the normal decompression mode is small enough to remove -Os. Decompression Time(counts) Normal UA enabled -Os 6717 3447 -O2 6720 2728 Note: ARM v7, Kernel 3.4 counter freq. = 32768 HZ UA(Unaligned Access) gcc version 4.6.2

Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Florian Fainelli <florian@openwrt.org>
Cc: Yann Collet <yann.collet.73@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Locasto <amperific@gmail.com>