omap: iovmm: Fix compiler warning

This patch fixes these compiler warnings:

arch/arm/plat-omap/iovmm.c: In function 'vmap_sg':
arch/arm/plat-omap/iovmm.c:202: warning: passing argument 1 of
 'flush_cache_vmap' makes integer from pointer without a cast
arch/arm/plat-omap/iovmm.c:202: warning: passing argument 2 of
 'flush_cache_vmap' makes integer from pointer without a cast
arch/arm/plat-omap/iovmm.c: In function 'sgtable_fill_vmalloc':
arch/arm/plat-omap/iovmm.c:393: warning: passing argument 1 of
 'flush_cache_vmap' makes integer from pointer without a cast
arch/arm/plat-omap/iovmm.c:393: warning: passing argument 2 of
 'flush_cache_vmap' makes integer from pointer without a cast

Signed-off-by: Sanjeev Premi <premi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>