Use the new thumb_get_instruction_word/thumb_set_instruction_word
helpers throughout.
Style cleanup (missing spaces).
Move Thumb MOVW/MOVT handlers into Thumb relocation section of file.
GCC 4.9 also generates R_ARM_THM_MOVW_ABS_NC and R_ARM_THM_MOVT_ABS,
as an alternative to ABS32.
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>