ARM: dts: Fix mmc order for omap3-gta04

Commit a1ebdb37 ("ARM: dts: Fix swapped mmc order for omap3")
introduces general mmc aliases. Let's tailor them to the need
of the GTA04 board which does not make use of mmc2 and mmc3 interfaces.

Fixes: a1ebdb37

 ("ARM: dts: Fix swapped mmc order for omap3")
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Message-Id: <dc9173ee3d391d9e92b7ab8ed4f84b29f0a21c83.1646744420.git.hns@goldelico.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>