package/jpeg: properly indent in menuconfig

package/jpeg: properly indent in menuconfig

Since there is a variable definition between the definition of
BR2_PACKAGE_JPEG and the choice depending on it, the choice is
not indented bewlo the "jpeg support" prompt, like we like to
have:

    [*] jpeg support
        jpeg variant (jpeg-turbo)  --->

Move the BR2_PACKAGE_JPEG right before the choice (really, move
BR2_PACKAGE_JPEG_SIMD_SUPPORT before BR2_PACKAGE_JPEG, but diff
finds the move of BR2_PACKAGE_JPEG is smaller to display):

    [*] jpeg support
          jpeg variant (jpeg-turbo)  --->

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>