ARM: OMAP4: hwmod data: I2C: add flag for context restore

Restore of context is not done for OMAP4. This patch
adds the OMAP_I2C_FLAG_RESET_REGS_POSTIDLE in the OMAP4
hwmod data which activates the restore for OMAP4.
Currently the OMAP4 does not hit device off still the
driver may have support for it.

Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Wamsley <paul@pwsan.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>