staging: rtl8188eu: Use ODM_REG_IGI_A_11N and ODM_BIT_IGI_11N in odm_DIGInit()

ODM_REG(IGI_A, pDM_Odm) and ODM_BIT(IGI, pDM_Odm) macros produce
ODM_REG_IGI_A_11N and ODM_BIT_IGI_11N respectively after preprocessing.

Signed-off-by: navin patidar <navin.patidar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>