common: lcd.c: fix data abort exception when try to access bmp header

Changes:
- le16_to_cpu() to get_unaligned_le16()
- le32_to_cpu() to get_unaligned_le32()
when access fields in struct bmp header.

This changes avoids data abort exception caused by unaligned data access.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>