[ARM] pxa: make MFP configuration processor independent

[ARM] pxa: make MFP configuration processor independent

There are two reasons for making the MFP configuration to be processor
independent, i.e. removing the relationship of configuration bits with
actual MFPR register settings:

   1. power management sometimes requires the MFP to be configured
      differently when in run mode or in low power mode

   2. for future integration of pxa{25x,27x} GPIO configurations

The modifications include:

1. introducing of processor independent MFP configuration bits, as
   defined in [include/asm-arm/arch-pxa/mfp.h]:

	bit  0.. 9 - MFP Pin Number (1024 Pins Maximum)
	bit 10..12 - Alternate Function Selection
	bit 13..15 - Drive Strength
	bit 16..18 - Low Power Mode State
	bit 19..20 - Low Power Mode Edge Detection
	bit 21..22 - Run Mode Pull State
	and so on,

2. moving the processor dependent code from mfp.h into mfp-pxa3xx.h

3. cleaning up of the MFPR bit definitions

4. mapping of processor independent MFP configuration into processor
   specific MFPR register settings is now totally encapsulated within
   pxa3xx_mfp_config()

5. using of "unsigned long" instead of invented type of "mfp_cfg_t"
   according to Documentation/CodingStyle Chapter 5, usage of this
   in platform code will be slowly removed in later patches

Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>