arm64: zynqmp: Remove description for 8T49N240

8T49N240 driver was never upstreamed by IDT and there is no user of this
driver that's why remove description for this chip with also remove this
driver.

Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/52aec21f121713160d5953b0a41a10cb196482b3.1699428990.git.michal.simek@amd.com