ARM: EXYNOS: change HAVE_SAMSUNG_KEYPAD to KEYBOARD_SAMSUNG

Commit 6b5ab4f4 ("ARM: EXYNOS: Add Exynos4 device tree enabled
board file") added select HAVE_SAMSUNG_KEYPAD if INPUT_KEYBOARD

to the MACH_EXYNOS4_DT Kconfig entry. But there's no Kconfig symbol
HAVE_SAMSUNG_KEYPAD. Since this select statement depends on
INPUT_KEYBOARD this entry should select KEYBOARD_SAMSUNG instead.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>