kmp204x: introduce QRIO GPIO functions

kmp204x: introduce QRIO GPIO functions

The QRIO GPIO functions can be of general interest. They are thus added
to a qrio.c and their prototype are available from kmp204x.h. The QRIO
prst function are also included in this file, as well as the functions
required for the I2C deblocking support (open-drain).

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
[York Sun: Remove extra blank line in board/keymile/kmp204x/qrio.c]
Signed-off-by: York Sun <yorksun@freescale.com>