limare: add assembler version of texture_16_swizzle_fullblock

Credits go to Gilead Kutnick <exophase at gmail.com>
Makefile: add texture asm
limare: remove C-style texture_16_swizzle_fullblock...

and use the assembler variant instead.
limare: texture: minor code style adjustments
limare: texture: check for 128-bit alignment before using NEON asm
limare: texture: move perf debug code around