[MTD] Pre-CFI Sharp chip driver: Some speedups and cleanups

Remove useless udelay(100) after status value already read.  Poll
for status OK with reduced udelay if not immediate OK status return.

Fix read and compare of 32-bit status value using 16-bit variable.

Include slab.h since kmalloc/kfree are called.

Signed-off-by: Todd Poynor <tpoynor@mvista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>