[DRIVERS] Correcting i.MX GPIO driver.

The i.MX GPIO driver requires software managed IRQs, in order to allow using
GPIO pin specific IRQ handler.
[DRIVERS] Correcting MMC and generic MMC GPIO detection drivers.

The MMC host lock was not initialized, and the GPIO IRQ edge type selection was
not set.
[DRIVERS] Adding MMC/SDHCI card and write protect GPIO detections.
[MAKEFILE] Avoid quoting the "VMM_MODNAME" macro variable on the command line.

Since the "VMM_MODNAME" macro variable will be used for defining "modtbl" and
"nidtbl", it must not contain double quotes.
[CORE] Avoid declaring "nidtbl" and "modtbl" structures as unused and static.

As being declared as static and unused, the "nidtbl" and "modtbl" structures
are removed from the objects compiled in -O1 or more optimized level, leading
to empty ".nidtbl" and ".modtbl" sections.
The module tree tables are now named with "__modtbl__" and the module name
(the compiled file name) to avoid multiple definitions.